A semiconductor device with a fuse 3a to be cut for a circuit modification, of which passivation film coating the uppermost wiring layer is formed in a two-layer structure including a first insulating film 11 with high filling capability and a second insulating film 12 blocking penetration of moisture or impurities. An opening 21 formed in a specific depth through the insulating films on the fuse 3a is coated by a third insulating film 13 with the blocking capability. This prevents the penetration of moisture or impurities, and the corrosion of the fuse 3a.