An in-vehicle electronic device is provided which can ensure resistance to static electricity for the in-vehicle electronic device covered with a resin case, is more downsized smaller in the number of components, and inexpensive. An in-vehicle electronic device 43 includes: a resin housing (resin case) 5; a control board 7 that is covered with the housing, and accommodated within the housing a battery harness 27 that is a power wiring which supplies power to the control board; a signal harness 31 that is an input/output signal wiring that transmits an input/output signal to the control board; and a metal bracket 1 that fixes the resin housing to a vehicle main body. In the device, a distance between a projection 35 of the metal bracket 1 and the battery harness 27 is set to be shorter than a distance between the projection 25 of the metal bracket 1 and the signal harness 31 to form a discharge gap 33.