QUALITY INSPECTION DEVICE

PROBLEM TO BE SOLVED: To inspect precisely existence of a defect on a test surface without being influenced by falling dust or the like in the middle of conveyance of a test object. SOLUTION: In the middle of conveyance, by a conveyance means 1, of a test object, for example, a corrugated cardboard 51, in the state where a printed test surface thereof is faced downward, the test surface is illuminated by illumination light sources 2, 3, and imaged by an imaging camera 7 of an imaging device 6 through a light transmitting plate 13. The imaging camera 7 is housed in an optical box 8 having the light transmitting plate 13 on the front thereof. The light transmitting plate 13 is placed at an angle relative to a horizontal plane, to make adhesion of falling dust or the like difficult. Hereby, even if the dust or the like adheres by any chance, it can be removed simply and surely by spraying air or the like.