PURPOSE: To rapidly return a pointer to a zero position and to attain to reduce the capacitance of a capacitor as an auxiliary power source, by providing a circuit for detecting the cut-off of a power source and the zero return circuit of the pointer.

CONSTITUTION: A detection circuit 46 detects the cut-off of a power source 26 for supplying driving voltage to a cos θ generator 8 and a sin θ generator 10 while a zero return circuit 40 responds to the detection signal of the detection circuit to forcibly discharge a capacitor 38 connected to the input parts of both generators 8, 10 and a pointer is transferred to a zero position. As mentioned above, because the capacitor 38 is forcibly discharged at the OFF time of the power source and the inputs of the generators 8, 10 are controlled to zero inputs, the pointer can be rapidly returned to the zero position according to zero return operation. In addition, the capacitance of a capacitor 32 as an auxiliary power source can be reduced.