PURPOSE: To correctly transfer the input information by the pulse width to the pulse width information on the output side.

CONSTITUTION: A pulse width/voltage/pulse width converting circuit is constituted of an integrating circuit 2 integrating input pulses, a sample hold circuit 3 sample-holding the integrated value of the integrating circuit 2, an analog arithmetic circuit 4 calculating the held value and the required arithmetic signal, and an output pulse generating circuit 5 generating the pulses with the required pulse width from the integration signal and the output of the analog arithmetic circuit 4. When a series of analog arithmetic processes are applied to the input pulse information, the drift of offset and the deterioration of linearity are prevented between the input and output, and the control signal information generated on the transmission side can faithfully be transferred to the output side.