Disclosed is a key sheet having a base sheet equipped with a hard resin plate and a key sheet manufacturing method, wherein a reduction is achieved in the thickness of the base sheet and in the effort and cost for the molding. Further, accurate depressing operation is realized without impairing the outward appearance of the key sheet. The key sheet has a hard base plate having a communicating groove connecting through-holes with each other. The communicating groove has a connecting portion formed so as to be continuous and integral with operating portions formed respectively at the through-holes. Thus, there is no need to form inlets for a rubber-like elastic material respectively corresponding to the through-holes in the mold. As a result, the mold structure can be simplified to thereby achieve a reduction in cost. Further, since the entire front or back surface of the hard base plate is not covered with the rubber-like elastic material, it is possible to achieve an overall reduction in the thickness of the base sheet.