A circuit coupling adhesive which is superior in heat resistance and moisture resistance is provided. The circuit coupling adhesive of the present invention can be used for purposes where high performing reliability is required, since it exhibits satisfactory electroconductive/insulative performance at connection of electrodes, etc. and the characteristics will not be varied so much even after a long period of use in a high temperature and high humidity environment. The circuit coupling adhesive comprises, as the essential ingredients, an epoxy resin, a latent curing agent, inorganic fillers having an average particle diameter of 500 nm or less, and electro-conductive particles. By mix a sufficient amount of inorganic fillers having an average particle diameter of 500 nm or less, the coefficient of thermal expansion can be decreased and the heat resistance and moisture resistance can be improved.