The present invention provides an adhesive sheet, which can fix an electronic material (such as a raw sheet). Reattachment of a cut chip is prevented after the electronic material is cut on the adhesive sheet. The adhesive sheet comprises an extensible base material and an adhesive layer disposed on one or both sides of the extensible base material. The adhesive layer contains a binder and heat-expandable microspheres. When the adhesive sheet is in close contact with a to-be-bonded object, the relation between the thickness of the adhesive layer and the elastic modulus based on a nanoindentation method is 0.05 (MPa*[mu]m-1)<=(1/thickness ([mu]m) of the adhesive layer * modulus (MPa) of elasticity based on the nanoindentation method <=40(MPa*[mu]m *1). The adhesive force of the adhesive sheet to SUS304BA is preferably 0.1 N/20 mm or more.