He’ll never beat the rap if he’s stewing behind bars.

Alleged NYPD cannibal wannabe Gilberto Valle is asking a judge to temporarily free him from the slammer so he can prepare for his Jan. 22 trial.

His solitary confinement in the Metropolitan Correctional Center in lower Manhattan makes it “impossible” for him to review some 1 million pages of evidence, public defender Julia Gatto said in papers filed yesterday.

Gatto’s motion doesn’t say whether taxpayers will foot the bill for transporting and guarding Valle.

Valle, 28, has been repeatedly denied bail since his October arrest on charges of scheming to rape and eat women.