PURPOSE: To obtain the image sensor driving circuit not outputting any signal to a common line output terminal and not generating a switching noise when the reading of a signal is not performed.

CONSTITUTION: The image sensor driving circuit is provided with first switches 101 to 164 charging the image sensor to a reference voltage, buffer amplifiers 201 to 264 connected to the output of the image sensor, second switches 301 to 364 controlling the output of this buffer amplifier, a shift register 5 controlling the first and the second switches, and a third switch 4 outputting the output of the buffer amplifier to a common line 6. By applying an enable signal ENA having the same phase with the clock signal of the shift register to this third switch, the reading signals from the image sensors IN1 to IN64 are transferred to a common line output terminal COM. The enable signal is passed at the time of signal reading operation responding to the output of the shift register 5, and the generation of the switching noise is prevented by providing a control circuit 7 having a gate circuit 9 preventing the enable signal other than the above case.