To reduce the image fetching time of a wart and to accelerate its processing by freely divide and open/close a face light-emitting means so as to superpose a joint edge on a main body part where the lead of the work is not projected.

A shutter 41 is provided for a stage 21 for fetching an image, consists of supporting body 42 and the face light-emitting body and is arranged to position at the back face of the work 2 held by the tip of the work absorbing nozzle of a work holding mechanism. The shape of the shutter 41 is divided so as to position the joint edge 44 on a diagonal of a rectangular work 2 projecting leads 20 at its sides. Each piece of the shutter 41 of the sage 21 is respectively fixed to slide guides 27 and 28 fixed to a frame, and the slide guides 27 and 28 are connected to air cylinders 29 and 30. Consequently, by driving the air cylinders 29 and 30, the shutter 41 is moves for opening/closing operation while being guided by the slide guides 27 and 28.