To provide a short-cut detection circuit for detecting a short-cut of a load circuit of an electric device which detects a short-cut with good accuracy without electrifying a heavy current even when the resistance value of the load circuit varies widely and reduces the ranges of values of the measurement voltage or the measurement current for detection of a short-cut.

One end of a load circuit 3-3 is connected to an electric power supply terminal of a main electric power source 3-1 through a first switch 3-2, and the other end is connected to a ground terminal through a second switch. For a short-cut detection circuit, a resistance 1-2 and a diode 1-3 for detection of a short-cut are connected to an electric power supply terminal 1-1 supplying a voltage for an electronic control unit lower than the supply voltage of the main electric power source to detect a voltage between the connection points of the resistance and the diode by a control part 1-5. The control part 1-5 determines the load circuit to be in a short-cut state when, with the first switch 3-2 being non-conductive and the second switch being conductive, the voltage between the connection points of the resistance 1-2 and the diode 1-3 is equal to or lower than a specified threshold voltage.