PURPOSE: To facilitate repair, exchange and cleaning, etc., of a bottom mounted electrode.

CONSTITUTION: The device consists of the bottom mounted electrode 15 held freely detachably through an opening 2, a expansion cylinder 21 having its base end part connected to the opening 2 of an electrodeposition cell 1 being freely in extendable and contractable in axial direction and capable of covering the bottom mounted electrode 15, a first opening and closing means 31 to open and close a tip of the expansion cylinder 21, and a second opening and closing means 29 to open and close an end part of the expansion cylinder 21, at the bottom of the electrodeposition cell 1. In this way, cleaning, etc., of the bottom mounted electrode can simply be carried out.