Chinamayanand is being taken for a medical examination following which he was taken to the the court of Chief Judicial Magistrate. The court remanded Chinmayanand to 14-day judicial custody.
Opposition parties have alleged the arrest has come come in late and and the victim had already faced a lot of damage.
"The Bharataiya Janata Party clearly believes whosoever has violated the laws should face action. BJP never tries to protect any accused who has committed a crime ,"Rakesh Tripathi, UP BJP spokesperson.
Chinmayanand was admitted to Shahjahanpur government hospital on Wednesday after his health deteriorated.
The 73-year-old politician was being treated by a team of doctors in his Mumukshu ashram where he has been held under house arrest since September 13. .
Chief Medical Superintendent M.P. Gangwar said: "After his condition worsened on Wednesday, he has been shifted to the medical college hospital and admitted in ward number 8."
Chinmayanand has chronic diarrhoea. He complained of uneasiness late on Monday and the doctors were called in. This was hours after the law student had appeared before the court to record her statement.
The 23-year-old law student has accused Chinmayanand of sexually harassing her repeatedly and blackmailing her.
The student, on Wednesday, threatened to end her life if Chinmayanand was not arrested. She said that it had been over 15 days since she recorded her statement but the Special Investigation Team (SIT) had not yet arrested the accused.
A member of the investigating team said, on condition of anonymity, that they would wait for Chinmayanand to recover before further action could be initiated.
(With additional information from IANS)