A component presence/absence judging apparatus judges the presence/absence of a component through a registration step and an inspection step. The registration step comprises an ante-mounting color information acquisition step, a post-mounting color information acquisition step and an inspection area determination step. Ante-mounting color information is acquired from an ante-mounting image taken at a predetermined portion on an ante-mounting board. Post-mounting color information is acquired from a post-mounting image taken at the predetermined portion on a post-mounting board. Then, a section having a large difference between both color information of the ante-mounting image and the post-mounting image is identified and is determined as an inspection area. At the inspection step, the presence/absence of the component at a predetermined place on each inspection board to be inspected is judged in dependence on the color information on the determined inspection area.