A method of mounting a semiconductor chip in which an IC chip is mounted by filling a gap between the chip and a substrate with adhesive which functions as an underfill. The fillet of the underfill is made to have a preferable shape. To accomplish this, a head IC chip provided with bumps is placed on a suspension that is covered with the underfill adhesive and is provided with pads. A bonding tool presses the head IC chip and applies ultrasonic oscillation to the head IC chip, so that the bumps are properly bonded to the pads. When the head IC chip is pressed and subjected to ultrasonic oscillation, the ultraviolet rays 108 are emitted so as to harden the peripheral portion 151a of the adhesive 151 spread out between the head IC chip 11 and the suspension 12.