Common Pleas Court Judge M. Teresa Sarmina rejected the defense's bail request, The Philadelphia Inquirer reported.
The defense argued Lynn should be released on bail because there is "better than a 50-50 chance" the state Superior Court will rule in their favor on appeal.
Assistant District Attorney Patrick Blessington argued that, under state law, a criminal defendant convicted and sentenced to more than two years in prison has no right to bail. Lynn was sentence to three to six years in prison.
Lynn, the 61-year-old priest who was the Catholic Archdiocese of Philadelphia's secretary for clergy from 1992 to 2004, was found guilty of child endangerment for failing to investigate allegations that priests sexually abused minors.
"I'm denying the motion based on the serious nature of the conduct Msgr. Lynn committed," Sarmina said at the hearing.