An adhesive sheet having high adhesion and removability, low metal corrosion, small outgas generation, and particularly suitable for adherence to an electronic part, which sheet includes an adhesive layer provided for at least one surface of a substrate sheet, in which a pressure-sensitive adhesive forming the adhesive layer includes a resin composition mainly formed of an acrylic copolymer obtained by blending a carboxyl group-free acrylic copolymer obtained by copolymerizing the following components (A) to (C) with (D) an isocyanate-based cross-linking agent: (A) 76.999 to 94.999% by mass of an alkyl(meth)acrylate; (B) 5.0 to 23.0% by mass of an ethylenically unsaturated group-containing morpholine-based compound; and (C) 0.001 to 1.5% by mass of a functional group-containing unsaturated monomer; and a ratio M2/M1 of the mole number (M2) of isocyanate groups in the component (D) to the mole number (M1) of functional groups in the component (C) is 1.5 to 15.0.