Pressure-sensitive adhesive sheet and process for producing adherend laminate

Provided is a heat-peelable pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer which, even when heated under severe conditions (for example, 100 DEG C, 3 hours), can retain the expanded state without shrinking and can thereafter be easily peeled from the adherend. The pressure-sensitive adhesive sheet 1 includes a first pressure-sensitive adhesive layer 33, which comprises a heat-expandable pressure-sensitive adhesive composition comprising a thermally expanding agent and a pressure-sensitive adhesive. The pressure-sensitive adhesive sheet 1 is characterized in that the first pressure-sensitive adhesive layer 33 has been formed so as to satisfy relationships 1 and 2 and requirement a, wherein "S0" is the surface area of the first pressure-sensitive adhesive layer 33, "Ra" is the arithmetic average roughness of the surface of the first pressure-sensitive adhesive layer 33a which was heated at 100 DEG C for 3 hours, "H1" is the upper-limit height which is the highest point in the reces