A purpose of this invention is to suppress radiation noise while satisfying demands for higher speeds and higher image qualities of a semiconductor laser driving device in a laser beam printer or the like. A laser driving circuit includes a first wiring pattern and a second wiring pattern which are connected to a main wiring pattern, a first circuit which is connected to the first wiring pattern and has a semiconductor laser element (7) and a laser driving device for driving the semiconductor laser element, a second circuit which is connected to the second wiring pattern, has a compensation element and a compensation driving device, and compensates for noise in the first circuit, and a common mode choke coil which is connected to the first and second wiring patterns and selectively increases impedances to in-phase signal components in a signal flowing through the first wiring pattern and the first circuit and a signal flowing through the second wiring pattern and the second circuit.

 
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