A mounting method and a mounting device are provided, which can mount an electric component with high reliability by using an adhesive. The mounting method includes thermocompression bonding an IC chip onto a wiring board by using an anisotropic conductive adhesive film. During the thermocompression bonding, a top region of the IC chip is pressed against the wiring board with a predetermined pressure, and a side region of the IC chip is pressed with a pressure smaller than the pressure applied to the top region of the IC chip. An elastomer having rubber hardness of 40 or more and 80 or less is used for a compression bonding portion of a thermocompression bonding head. The anistropic conductive adhesive film contains a binding resin having melting viscosity of 1.0×102 mPa·s or more and 1.0×105 mPa·s or less.