A protection circuit device using a MOSFET has a plural of conductive paths separated electrically, a MOSFET chip integrating two power MOSFETs in one chip where a gate electrode and a source electrode are fixed on the desired conductive path, conductive material provided on a common drain electrode of the MOSFET, and insulating resin covering said MOSFET and supporting said conductive path in one body. Removing a drawing-around of the common drain electrode and fixing the source electrode directly on the conductive path, low ON-state resistance is realized.