A dimming device comprising: a dimming circuit which controls dimming of a lighting load; a step-down chopper circuit connected to the lighting load, the step-down chopper circuit being configured to perform a high frequency chopper operation; characterized in that the dimming circuit includes: a first current adjusting unit adapted for receiving a PWM dimming signal and for controlling an amplitude of a current flowing through the lighting load by controlling the high frequency chopper operation such that the amplitude of the current increases if an on-duty ratio of the received PWM dimming signal including a high level and a low level decreases and the amplitude of the current decreases if the on-duty ratio of the received PWM signal increases; and a second current adjusting unit adapted for receiving the PWM dimming signal and for controlling continuity and discontinuity of the current flowing through the lighting load by controlling the step-down chopper circuit to stop the high frequency chopper operation while a level of the received PWM dimming signal is the high level and to perform the high frequency chopper operation while the level of the received PWM dimming signal is the low level, wherein an amount of light emitted from the lighting load is adjusted by simultaneously performing a control by the first current adjusting unit and a control by the second current adjusting unit. a dimming circuit which controls dimming of a lighting load; a step-down chopper circuit connected to the lighting load, the step-down chopper circuit being configured to perform a high frequency chopper operation; characterized in that the dimming circuit includes: a first current adjusting unit adapted for receiving a PWM dimming signal and for controlling an amplitude of a current flowing through the lighting load by controlling the high frequency chopper operation such that the amplitude of the current increases if an on-duty ratio of the received PWM dimming signal including a high level and a low level decreases and the amplitude of the current decreases if the on-duty ratio of the received PWM signal increases; and a second current adjusting unit adapted for receiving the PWM dimming signal and for controlling continuity and discontinuity of the current flowing through the lighting load by controlling the step-down chopper circuit to stop the high frequency chopper operation while a level of the received PWM dimming signal is the high level and to perform the high frequency chopper operation while the level of the received PWM dimming signal is the low level, wherein an amount of light emitted from the lighting load is adjusted by simultaneously performing a control by the first current adjusting unit and a control by the second current adjusting unit. a first current adjusting unit adapted for receiving a PWM dimming signal and for controlling an amplitude of a current flowing through the lighting load by controlling the high frequency chopper operation such that the amplitude of the current increases if an on-duty ratio of the received PWM dimming signal including a high level and a low level decreases and the amplitude of the current decreases if the on-duty ratio of the received PWM signal increases; and a second current adjusting unit adapted for receiving the PWM dimming signal and for controlling continuity and discontinuity of the current flowing through the lighting load by controlling the step-down chopper circuit to stop the high frequency chopper operation while a level of the received PWM dimming signal is the high level and to perform the high frequency chopper operation while the level of the received PWM dimming signal is the low level, wherein an amount of light emitted from the lighting load is adjusted by simultaneously performing a control by the first current adjusting unit and a control by the second current adjusting unit.