A component-mounting machine including an LED lighting device configured to illuminate an imaging target that is to be imaged by a camera loaded on the component-mounting machine; and an illumination light amount adjusting device configured to adjust in steps with a specified gradation quantity an illumination light amount of the LED lighting device. The LED lighting device uses two types of LED elements with different brightness levels, and the illumination light amount adjusting device is configured to adjust in steps with a specified gradation quantity a pulse width or a current value of a current flowing through low-brightness LED elements that are the LED elements with a lower brightness level out of the two types of LED elements so as to adjust in steps with a specified gradation quantity an emitted light amount of the low-brightness LED elements while maintaining a specified level of illumination light amount.