To provide a stage system with which a proscenium or a vertical acoustic reflection panel can be easily moved and beautifully housed while saving a space.

This system is provided with a front acoustic reflection panel 20 which is erected almost vertically to a stage 10 and can be moved in the longitudinal direction of stage 10 by a runner 60, side acoustic reflection panels 30a and 30b respectively linked through hinges 31 to both the side ends of front acoustic reflection panel 20 so as to horizontally move, and gate-shaped procenium 50 which is erected so as to be moved almost vertically to the stage 10 by being hung through a roller device to a guide rail arranged on the ceiling section of stage 10, can be moved in the longitudinal direction of stage 10 by a runner and has a frontage. Then, by moving these facilities 20, 30a, 30b and 50 to the rear wall surface side of stage 10, the acoustic reflection panels 20, 30a and 30b can be housed in the frontage of procenium 50 on the same plane as the procenium 50.