The accused Siddhant Ganore had moved the court earlier this month, seeking bail on the ground that he was of "unsound mind".
Accepting the prosecution's argument that Ganore's prayer could not be granted since the crime was of serious nature, special judge Shayana Patil rejected his bail plea.
Ganore was arrested on May 25 from Rajasthan, two days after his mother Deepali Ganore was found dead at their residence in Vakola in Mumbai, when his father had gone to the police station.