CIRCUIT DEVICE

A circuit device for a vehicle is arranged in a power supply path. In the circuit device, a first conductive pattern and a second conductive pattern are arranged on an insulating layer. The first conductive pattern and the second conductive pattern are connected to each other by a fuse (circuit element). A bus bar is arranged on the first conductive pattern. Therefore, when a current flows through a conductor constituted by the bus bar and the first conductive pattern, the amount of heat generated in the conductor is small.