ELECTRONIC CONTROL DEVICE FOR VEHICLE

In a vehicle electronic control unit (41), a semiconductor device (52) is mounted on a printed circuit board (51). In the semiconductor device (52), a custom chip (57) and a microcomputer chip (58) are arranged in a package (54), (55) in a stacked manner. On the custom chip (57), a first input circuit and a first output circuit for inputting and outputting signals or the like to and from the microcomputer chip (58) are formed. On the printed circuit board (51), a second input circuit and a second output circuit for inputting and outputting signals or the like to and from the microcomputer chip (58) while bypassing the custom chip (57) are formed.