To provide a drive circuit of a light emitting element such as an LED, etc., which can output a pulse current of a predetermined level by suppressing the influence of the change of a temperature or a power source voltage or of the unevenness of the element.

When an n-type MOS transistor 10 is turned on, power is supplied from a switching power source 60 to the LED, and a current of the LED is detected by a resistor 20. An error signal Serr of this detected signal Sfb and a target signal Sref is generated in an error signal generator 30, and averaged in a signal holder 40. Supply power to the LED is controlled in response to the averaged error signal SerrA. When an n-type MOS transistor 10 is changed from on to off, the power supply to the LED is stopped, and the error signal SerrA is held in the signal holder 40. When the n-type MOS transistor 10 is changed from off to on, the averaging of the error signal Serr is started at the signal level of the held error signal SerrA used as an initial level.