To precisely detect short circuit between signal lines which connect a waveform shaping circuit for shaping waveforms of input signals with a signal processing device for processing signals, whose waveforms are shaped, in a device for detecting the short circuit.

The device for detecting the short circuit is provided with an IC 22 for inputting wheel speed and a main IC 32. The IC 22 for inputting the wheel speed shapes the waveforms of sinusoidal signals outputted by wheel speed sensors 14-20 to pulse signals. The main IC 32 is connected with the IC 22 for inputting the wheel speed through the signal lines 24-30 and processes the signals whose waveforms are shaped. The IC 22 for inputting the wheel speed shaped the waveforms of the each sinusoidal signal so that the each sinusoidal signal is converted to the pulse signals having different signal levels each other. The main IC 32 respectively memorizes rated values of high voltage and low voltage of each voltage supplied through the signal lines 24-30 and determines whether the each voltage actually supplied exists within the specification values or not. When the voltage actually supplied does not exist within the specification values, the device for detecting the short circuit determines the short circuit between the signal lines 24-30.