A semiconductor device has a control terminal attached to a patterned insulating substrate; a first projection formed on the control terminal; a second projection formed on the control terminal; a concave formed between the first projection and the second projection; a resin case disposed to cover the patterned insulating substrate, and having an opening for passing the control terminal therethrough; a first concave portion; a beam portion disposed at the opening of the resin case; a second concave portion formed in the beam portion; a resin block inserted into the opening of the resin case and sandwiching the control terminal together with the sidewall of the opening of the resin case to fix the control terminal to the resin case; a convex step portion; a third projection formed on a side surface of the resin block; and a fourth projection thinned on a bottom surface of the resin block.