Prof Ismail Mashal was detained on Thursday while handing out free books.
He rose to prominence after he tore up his academic records live on television in protest against the Taliban’s ban on university and secondary school education for women and girls.
Prof Mashal, 37, has been accused of “provocative actions” by the Taliban.
Eyewitnesses reported that the professor was slapped, punched and kicked by Taliban security forces during the arrest, however Abdul Haq Hammad said the professor was being treated well while in custody.
When the Taliban announced in December that female university students would no longer be allowed back to study until further notice, Prof Mashal closed his school completely, saying “education is either offered to all, or no one”.
A defiant man, he has promised not to stay silent on the matter, even if it costs him his life. Video of the moment he tore up his own academic records on live television went viral.
Since then, he has received many threats. But despite this, he’s appeared on local media almost every day, as well as giving out free books from a cart to anyone who dares to take one.
“The only power I have is my pen, even if they kill me, even if they tear me to pieces, I won’t stay silent now,” Prof Mashal told the BBC’s Yalda Hakim last month.
He also said that more men must rise up to protest the restrictions against women.
He said he was certain that eventually the Taliban would try to silence him – but remained adamant that it was a price worth paying.