Are there many people believing in Buddhism?

There are many different kinds of Buddhism and they are very different from each other. I have been a Nichiren Buddhist, practicing with the Soka Gakkai, for 25 years. Nothing on Earth has ever brought me so much joy. I firmly believe that Buddhism will soon become the largest religion in the world. Perhaps that's why there's so much talk about it here.

Then, where is the origin of the first Buddhism? China, India, or somewhere else? Can anybody help me

http://sgi-usa.org/buddhism/resourceguide/resourceguide.html#section1 should give you some information. I am a member of the Nichiren sect Soka Gakkai. There is a plethora of information on the site.

Buddhism originated in Northeastern India around 500 BCE with the teachings of Siddhartha Guatama. Siddhartha became obsessed with finding the causes and cure for human suffering. After years of wandering and study under various Hindu holy men without success, he sat down beneath a tree and swore not to arise until he had solved the problem. After days of meditation, Siddhartha had an world-shaking experience, Enlightenment.

Siddhartha, now the Buddha (The Enlightened, or The Awakened One) rose from his seat and traveled to the pleasure Deer Park owned by a rich man to preach his first, and most important sermon. Three he preached the Four Nobel Truths and the Eight-Fold Path that would become the foundation for all other Buddhist teachings during the Buddha's lifetime.

The Buddha probably spoke Pali, and the Pali texts of the Theravada Buddhists are the oldest records we have of the Buddha's teaching. There are many similarities and borrowings from Hinduism in the early teachings. Buddhism radically departed from Hinduism in a number of important respects. Hinduism, even then, is a caste system that is highly dependent upon progressive merit over multiple transmigrations of the soul until finally the individual finds union in Brahma. Buddha rejected the caste system and the notion of people having souls, with only a few capable of experiencing Enlightenment. This was similar to the doctrines of the Jaine, also a Hindu offshoot a few hundred years earlier. The complexity of how Buddhism sprang from Hinduism is a large topic, too large for discussion here. I advise reading almost any of the many scholarly works available on the subject.

Buddhism was extremely popular and gained many followers during the Buddha's lifetime. Most early Buddhists became monks because the disciplines preached by the Buddha are extremely difficult for individuals working alone to master. The monks tended to congregate and discuss Buddhist Doctrine and the notion of shared merit, and the Bodhisatva ideal were born. This made it possible for common householders, businessmen, and even soldiers to become Buddhists without leaving their worldly responsibilities behind. Buddhism exploded out onto the larger world.

For a time India was united under a Buddhist ruler, Ashoka. Ashoka was a brutal soldier who gained his empire by war. Like Constantine, Ashoka was later stricken by conscience and converted to Buddhism. What followed was a mini-Golden Age in India. Unfortunately, after Ashoka died India reverted to Hinduism.

There were three principle Buddhist missionary streams away from India. One stream went West and in Guandara came into contact with Greek culture. Previously there were few Buddhist icons, but even today one can detect the Grecian influence in Buddhist statuary from Northern Asia. Buddhism traveled over the Silk Road to China, where it was received as the later writings of Lao Tzu. Lao Tzu was roughly contemporary to Confucius, but took a very different philosophical view of the world. See the Tao Te-Ching, and the writings of other Taoists like Chuang Tzu. This similarity in philosophical outlook greatly aided the introduction of Buddhism into China.

A second missionary effort went north into Nepal and Tibet. The great Milrepa brought Buddhism and oversaw its amalgamation with the nativist Bonpa religion. Being very isolated Tantric Buddhism remained very "pure" in its doctrine until relative recent times. The Dali Lama is thought by many to be only the latest in a long series of rebirths, and Tantric ritual s are unique amongst Buddhist Schools and Sects. The Dali Lama is today regarded by most Buddhists as a spokesman for our religion, even though we mostly don't follow the same teachings.

Bodhidarma took to the sea lanes and worked his way into Southern China, where he is the revered founder of the Chan, or Zen (J.) Schools. Buddhism became the principle religion of Southeast Asia, and is a mixture of Theravada and the Mahayana teachings of Bodhidarma and others.

Buddhism first came into Europe in the early 18th century, but was mostly of interest to Oriental scholars. A hundred years later some British eccentrics began practicing Buddhism, but their knowledge of the religion wasn't very deep. Today there are many more Buddhists in Europe, but Buddhism remains very much a minority religion.

During the late 19th century and early 20th century Buddhism was introduced as a practicing religion into the United States. It was often confused with Yoga and other esoteric Asian religions. After WWI the number of American Buddhists increased, but the real advance came after WWII. The works of Thomas Merton and Allan Watts had wide readership, and the appeal of Buddhism expanded it. A lot of the Beats were either Buddhist, or had Buddhist leanings, and that was a strong influence over the Hippy Generation. At the same time, famous Buddhist teachers from Japan were setting up shop in America. I studied under Roshi Suzuki at the Bush Street Zendo in San Francisco, and was married by a Buddhist Bishop at the Hewit Street temple in Los Angeles. In San Francisco the majority of us were Occidental, but at Hewit Street the whole congregation at the time was Japanese. There were many outstanding teachers in those years, and their efforts will be felt for decades to come.

Today there are many more Occidental priests, monks and nuns, and the number of Buddhist householders has greatly expanded.

There are a number of Buddhist threads on this forum. I suggest you find and read them. I think that most questions will have already been answered. If not, just ask.