To facilitate the fixation and release of a unit and to improve positioning accuracy by providing a unit side with an engaging part which moves in a direction where the part attaches and detaches to and from a device body and a device body side with a part to be engaged respectively.

The restitutive elastic force of a coil spring 121 acts on a retaining ring 122, urging a rod-like body 115 in an axial direction (a direction proximate to a block body 102) and causing the front end of the rod-like body 115 to be engaged and is inserted into an insertion hole 103 of the block body 102. Then, the outer peripheral surface of the rod-like body 115 and the inner peripheral surface of the insertion hole 103 abut on each other and, therefore, a first movable part 110 of a third transporting unit moving in a direction approximately orthogonal with the axial direction (engaging insertion direction) of the rod-like body 115 is restricted of its movement (a). At the time of maintenance, a knob 116 is gripped and is manipulated to be pulled to detach the rod-like body 115 from the insertion hole 103, by which the movement restriction of the first movable part 110 is released and the third transporting unit may be drawn out of the device body.