Electrode pads (5) and a solder resist (7) are disposed on the upper surface of a wiring board (1), and apertures (7a) are formed in the solder resist (7) so as to expose the electrode pads (5). Electrodes (4) are disposed on the lower surface of a semiconductor element (2). Electrodes (4) are connected to the electrode pads (5) by way of bumps (3). An underfill resin (6) is disposed in the area that excludes the solder resist (7) and the bumps (3) in the space between the wiring board (1) and the semiconductor element (2). Between the wiring board (1) and the semiconductor element (2), the thickness (B) of the solder resist (7) is equal to or greater than the thickness (A) of the underfill resin (6) on the solder resist (7). The volume (Vb) of the bumps (3) is less than the volume (Vs) of the apertures (7a).