A pressure-sensitive adhesive layer contains a base polymer and has properties of (1) and (2) below: in a case where a pressure-sensitive adhesive sheet A is laminated to an adherend X surface, they are left to stand at a temperature of 23° C. and a humidity of 30% for 12 hours, and the pressure-sensitive adhesive sheet A is then separated, (1) a water contact angle A on the adherend X surface from which the pressure-sensitive adhesive sheet A has been separated is 70° or less, and (2) a pressure-sensitive adhesive strength of a pressure-sensitive adhesive tape B with respect to the adherend X surface from which the pressure-sensitive adhesive sheet A has been separated is higher than that of the pressure-sensitive adhesive tape B with respect to the adherend X surface not subjected to any treatment.