To obtain a thermosetting resin composition containing a magnetic substance, which has excellent heat resistance and adhesiveness, absorbs electromagnetic waves radiated from the inside of a circuit and is previously processed into a sheet form, an adhesive sheet obtained by making the thermosetting resin composition containing a magnetic substance into a sheet form and a copper foil with an adhesive.

The thermosetting resin composition containing a magnetic substance is obtained by polymerizing a bifunctional epoxy resin with a bifunctional phenol in the equivalent ratio of epoxy group/phenolic hydroxy group of 1/(0.9-1.1) to give a straight chain epoxy polymer and mixing the polymer with a soft magnetic substance.