The Special Investigation Team (SIT) arrested Jha on the basis of evidences of his "involvement" in the scam, Patna's Senior Superintendent of Police (SSP) Manu Maharaj said.
With Jha's arrest, the number of those behind bars in the scam has gone up to 20.
The toppers scam rocked Bihar last month after Ruby Rai, who was earlier declared topper in arts, had failed to reply to basic questions about her subjects and described political science as 'prodigal science.'
Among those arrested are Ex-BSEB Chairman Lalkeshwar Singh and his wife Usha Singh, a former JD(U) MLA, a college principal Bachcha Rai and topper Rubi Rai.