PURPOSE: To provide the title resin sealing mold of semiconductor element having excellent molding capacity and lead frame shape while settling the point at issue of running resin into a gap between lead frame outside and a mold force during the resin molding step of the semiconductor element.

CONSTITUTION: Within the mold top and bottom forces A, B and a lead frame D during the resin sealing step of a semiconductor element, a protrusion J shapedly provided inside the lead frame D side in the same level as that of the frame thickness is arranged on the bottom force B in both end parts of a runner part G. Furthermore, a recession K opposing to a projection J of the bottom force B is provided in the lead frame outside while a crushing space M protruding in the gap L between the projection J of the bottom B and the lead frame outside recession K is provided in both parts of the runner G of the lead frame outside recession K so that a projection to cruch the crushing space M may be provided in the top force A when the mold top and bottom forces A, B are engaged with each other.