The MLA was produced before a court where the magistrate extended his judicial custody, prosecution lawyer said.
Kushwaha, who surrendered before CID-CB before arrest last month, is an accused in a murder case.
The murder took place in December 2012 in Dholpur and Kushwaha is one of the accused.
On July 5 the Rajasthan High Court had dismissed the anticipatory bail application of the Dholpur MLA. Following that he had surrendered.