To replace only a diffusion unit when it is stained, no that waste can be reduced, by providing a main unit formed with a flow path sucking an electronic part in a tip end part, and the diffusion unit formed of material diffusing light to be mounted removably in the main unit.

A flow path 11c penetrating a main unit 11 from its bate end part 11a to tip end part 11b is formed, a negative pressure is generated in this flow path 11c, so as to suck an electronic part to a lower end of the tip end part 11b. When a diffusion unit 12 is mounted in the main unit 11, a protruded edge 12a is engaged with a groove part 11e, an internal surface of the diffusion unit 12 is made in adhesion to a tapered surface 11d. Since an external diameter D1 of the diffusion unit 12 is larger than an external diameter D0 of the main unit 11 brightness is generated by this diffusion unit 12 behind the electronic part, and only an image of the electronic part is darkly observed, to be accurately recognized.