PURPOSE: To contrive thin formation of the subject device by guiding a holder with two guide members and connecting also both guide members with a connecting member.

CONSTITUTION: The 1st guide member 11 is provided in the case inserting direction to be erected on a bottom plate. The 2nd guide member 12 is parallel to the member 11, and is erected on the bottom plate. The connecting member 13 is laterally installed on the bottom plate, and is provided with a fitting hole 13a in the middle part to insert a screw. The member 13 is freely oscillated around this screw as an axis. Since the guide members 11 and 12 and the connecting member 13 are formed into narrow plate shapes respectively, the dimensional management of each part is facilitated. Then, the shapes are capable of hardly generating warps and distortion, etc., and even when a thin sheet metal is used, there is no fear of infeasibility of vertical movement of the holder 6, so that the device is reduced in thickness.