Investigators say the man did not have direct links to Islamic State or its recruits and appeared to be mainly a sympathizer and propagandist.
Police in the city of Bangalore said that Mehdi Masroor Biswas was arrested at his home after Britain's Channel 4 last week aired a program naming him as the source of the Twitter handle @ShamiWitness.
The account, which has been shut down, had 18,000 followers and cheered the actions of the militant group, which has taken hostages and killed civilians in its months-long military campaign to control vast parts of Iraq and Syria.
Analysts described the social media account as propaganda but were divided over whether its messages were incitement or free speech.
Bangalore Police Commissioner M.N. Reddi said in an interview that Biswas had confessed to being the owner of the account, which police alleged was a source of "incitement and information" for the militant group's English-speaking recruits and supporters.
“His Twitter handle had become a source of information for new recruits of ISIS," state police Director-General L. Pachau told a news conference, using an acronym for Islamic State. "He was in touch with the English-speaking terrorists from the terrorist group, thereby abetting them.”
Police said Biswas would be charged with "waging war" against countries allied with India and other terrorism-related charges.
In a brief interview with Channel 4, Biswas, described by authorities as an engineer working for a multinational company in Bangalore, India's high-tech hub, admitted owning the Twitter feed but denied wrongdoing.
"I haven't harmed anybody," he said. "I haven't broken any law...I haven't raised any war or any violence against the public of India. I haven't waged war against any allies of India. I want to state clearly that I won't resist arrest when the time comes."
Biswas told the channel that he believed beheadings are sanctioned by Islam but denied supporting Islamic State's reported beheadings of captives including Americans James Foley, Steven Sotloff and Peter Kassig. The @ShamiWitness account cheered Kassig's apparent beheading by the militants last month and posted links to a video of the incident.
Pachau said "many of his posts on Twitter were translations from Arabic tweets” but “some original tweets” are being investigated.
Parth M.N. is a special correspondent.