PURPOSE: To secure the wide setting space of the stage light, as well as to reduce the interference of noise of a control cable, by providing position detectors to detect the position variations of the vertical and the lateral movements of a ladder, and a control device connecting to the position detectors, and setting the position detectors at the fixing side in bulk.

CONSTITUTION: When a ladder 1 and a vertical and lateral moving device 4 are moved laterally by a built-in driving device, a wire 11 is drawn out from a wire reel 6 as the part of the moving amount, the winding number of the wire reel 6 is converted as the part of the moving amount, and a position detector 8 connected to the wire reel 8 outputs a signal according to the winding number to a control board 10 through a control cable 12. When the ladder 1 and the vertical and lateral moving device 4 are moved vertically, a position detector 9 connected to a wire cable 7 outputs a signal according to the wire winding number to the control board 10 through the control cable 12. The difference of the signals detected by the position detectors 8 and 9 is operated by the operation part of the control board 10.