PURPOSE: To provide the pulse width modulating circuit which imposes an image signal, inputted in synchronism with a clock signal, according to the image signal.

CONSTITUTION: This pulse width modulating circuit imposes pulse-width modulation on the image signal inputted in synchronism with the reference clock signal and has a delay time control circuit 101 which determines delay times ds and dr corresponding to the rise of the clock signal CLK according to the image signal and a pulse generating circuit 104 which generates a pulse signal Pw corresponding to the image signal according to those delay times ds and dr.