Illumination device maintains distance between eyes of user and object, and lights up desktop with appropriate illuminance. Illumination device includes light source for lighting up desktop, arm mechanism incorporates motor for moving position of light source, face camera detects position of eyes of user, desk cameras detects illuminance distribution on desk, image processing part calculates posture of user and distance between eyes of user and desk, based on face images obtained with face camera and desk images obtained with desk cameras, computation part calculates optimal light source position of light source wherein dispersion of illuminance distribution on desk is minimized, based on posture of user derived with image processing part and illuminance distribution obtained with desk camera, warning part that generates warning, in cases where distance is less than or equal to predetermined value, and control part operates arm mechanism such that light source moves to optimal light source position.