A semiconductor device includes: an inner substrate on which a semiconductor chip is mounted, and has a surface on which terminals including electric path terminals are formed; a lead frame which has a chip connecting electrode portion which is electrically connected to a surface of the semiconductor chip via a conductive bonding member, substrate connecting electrode portions which are electrically connected to the electric path terminals of the inner substrate, and horizontal surface support portions which bulge to the outside from the chip connecting electrode portion or the substrate connecting electrode portions; and pin terminals which are mounted upright over the inner substrate in a direction perpendicular to flat surfaces of the substrate connecting electrode portions of the lead frame, wherein the horizontal surface support portions bulge to the outside of the inner substrate.