PURPOSE: To attain a required stage effect at a large degree of freedom with a good reproduction by operating an stage effect rendering device according to a stage effect program on the basis of position information through ultrasonic signals from the moving body on a stage.

CONSTITUTION: Ultrasonic signals d1-d4 are transmitted from an ultrasonic wave generating device 30 of a body A moving irregularly on a stage. The signals d1-d4 are received by an ultrasonic wave detection unit 40, and at a CPU 10 coordinates information showing the position of the body A in a space coordinates system set on the stage 2, is obtained. The information is used as cueing signals and a stage effect rendering device is operated according to a predetermined stage effect rendering program. The device 30 is started through a wave generator 20 by means of the CPU 10, and after the body A reaches a set position, a lighting device 50, an accoustic device 60 and the like are operated.