<p>With the upper end of a shaft member (19) formed on a movable body (16) brought into contact with a support body (11) by biasing the movable body upward by a voice coil motor (22), the support body is lowered by a drive source (2) so as to mount a semiconductor chip (25) on a substrate (27) with a first press-fitting force. With the engagement and holding of the movable body onto the support body by a flange (21) formed on the shaft member (19) being released, a downward biasing force is applied to the movable body so as to mount the semiconductor chip on the substrate with a second press-fitting force smaller than the first press-fitting force.</p>