Justice Rajesh Dayal Khare dismissed the petition of Mishra, who held Secondary Education portfolio in the previous Mayawati government, saying his "application lacks merit".
The case filed against Mishra last year in Sant Ravidas Nagar district was pending before the court of Special Judge, Prevention of Corruption Act, Varanasi.
During preliminary inquiry, Mishra was allegedly found to be in possession of assets worth Rs 4.75 crore which was much in excess of his known income.
However, the court was of the view that "protection under the aforesaid section is available to a government servant who acts under the colour of his office in discharge of his official duty. Acquiring disproportionate assets beyond known source of income is not part of discharge of official duty of a minister.