PURPOSE: To protect a strain gauge from corrosion and maintain improved characteristics by successively forming an inorganic insulation film and an organic insulation film on the surface of the strain gauges, preventing the moisture of external air, and then screening the pin hole of the inorganic insulation film with the organic insulation film.

CONSTITUTION: In a load cell 1, an organic insulation layer 14 is uniformly laminated on the surface of a thin deformation part 6 of the surface of a Roberval mechanism and then a strain gauge 9 and a lead electrode 10 of a bridge circuit are formed on the surface. Namely, the lead electrode 10 is constituted by successively laminating a gauge resistance film 15, a temperature compensation film 16, and a conductive layer 17 and then the gauge 9 is in a structure where the compensation film 16 and the conductive layer 17 are eliminated from the surface of the resistance film 15. An inorganic insulation film 18 with a film thickness of 1000 consisting of SiO2 is laminated on the surface of the bridge circuit thus constituted and an organic insulation film 19 with a film thickness of 10μm consisting of polyimide is formed on the surface of the insulation film 18 and the gauge 9, thus preventing corrosion due to ambient moisture with the insulation film 18 without any hygroscopic property and then screening the pin hole of the insulation film 18 with the insulation film 19 of the pin hole.