A key switch sheet has a pressure sensitive adhesive layer for holding a contact spring by adhering to an apex portion of a dome-shaped contact spring at a back surface of a base material sheet. A thickness of the pressure sensitive adhesive layer at a region to be made to adhere to the apex portion of the contact spring is thicker than a thickness of the pressure sensitive adhesive layer at a peripheral region and thicker than or equal to a thickness of the pressure sensitive adhesive layer at a region where the base material sheet is made to adhere to a substrate.