To surely and readily judge or discriminate a conveying posture and a kind of an article that passes between a light source and an imaging device.

A fluorescent light 12 is disposed on a one side of a belt conveyer 11 at an inclination angle to the belt conveyer 11 and an imaging camera 13 is disposed on the other side of the belt conveyer 11 in opposition to the fluorescent light 12. An image processing device 14 that judges a conveying posture of an article 1' in accordance with an image of the posture of the article 1' stored in a memory and a signal from the imaging camera 13, is connected to the imaging camera 13. A projector 15 that is provided on the other side of the conveyer 11, emits a spot light which is reflected by a face of the article 1' opposing to a side of the imaging camera 13 to be incident on the imaging camera 13 only when the face is on a prescribed position.