PURPOSE: To carry out an inspection of all the display lamps, provided in each floor, in a cage.

CONSTITUTION: In this constitution, trouble information of a selected floor is lighted in in-cage display lamps 2a to 2n, 3a, 3b by a lighting command means for successively outputting a lighting command for lighting each display lamp one by one in each floor terminal device 13, 18, 23, current detecting means 26 for detecting a current for whether provided or not flowing in a power line 25 in each output of this lighting command, trouble memory means 28 for storing trouble information when detected no current, selecting means 5a to 5n for selecting an objective floor of an inspecting result and a trouble lamp displaying means.