"Agarwal was arrested from a place near a court here. He has been taken for interrogation in connection with the alleged horse trading during Rajya Sabha election," Deputy Superintendent of Police (CBI) A K Jha told PTI.
Agarwal was accused of horse trading during the biennial election last year.
Special CBI judge R K Chaudhary on Tuesday had cancelled Agarwal's bail plea on the request of the investigating agency, which claimed the lower court had granted bail despite evidence against him under the Prevention of Corruption Act.
The CBI had taken charge of the investigation, and conducted raids in the premises of at least 23 MLAs.