The leader of a right-wing group is among a number of new arrests that have followed an assault on women drinking in a bar in the city of Mangalore.
Pramod Mutalik heads the little known local group called the Sri Ram Sena (Army of Lord Ram) in the southern state of Karnataka.
Public and media outrage over the attack is growing and almost 30 people have been arrested so far.
Mr Mutalik says it is "not acceptable" for women to go to bars in India.
Speaking prior to his arrest, he said: "What my men did was right. The media is using this small incident to malign the BJP (Bharatiya Janata Party) government in the state."
For the past two days, he has argued that Saturday's assault on the women was justifiable because his men were preserving Indian culture and moral values.
It is thought Mr Mutalik was held in connection with an earlier complaint of inciting disharmony.
The BBC's Sanjoy Majumder in Delhi says the attack - which was filmed and then broadcast on national television - has shocked many Indians.
Television pictures showed the men chasing and beating up the panicking women - some wearing skirts. Some of the women, who tripped and fell, were kicked by the men.
Women's groups have strongly condemned the attack which has been described by the country's Women's Minister Renuka Chaudhury as an attempt to impose Taleban-style values.
Karnataka's BJP government has distanced itself from the attack. It said that it had nothing to do with Sri Ram Sena.
But our correspondent says that right-wing Hindu vigilante groups loosely linked to the BJP are active in many parts of India and have in the past targeted Muslim and Christian minorities as well as events such as Valentine's Day celebrations.
The Indian Express newspaper said such attacks "further encourage a latent puritanism, the kind that is deeply threatened by modernity and dark subversions like women enjoying alcohol".
The Hindustan Times newspaper, in an editorial, described the attackers as "thugs, not custodians".
"We have seen a rash of self-appointed moral guardians telling people what art is 'acceptable' and what they should wear or read. Such proscriptions have no place in a diverse democracy like ours," the newspaper wrote.
"The Sri Ram Sena goons... should be made an example of to deter future self-righteous busybodies who give Ram and India a bad name."