To provide a polyimide sheet having a water absorption rate equivalent to that of a general polyimide sheet produced from polyimide powder and a size which can not be molded by a polyimide sheet produced from polyimide powder.

The polyimide sheet is produced by laminating a plurality of polyimide films. A dimensional change ratio in an optional direction of one side of the polyimide sheet after being immersed in water for 1,000 h is 0.2% or below. Preferably, the polyimide sheet has a water absorption rate of 1% or below and a volume of at least 320 cm3, and the area of one side of the sheet is at least 1,600 cm2.