PURPOSE: To reduce a snore generated in the course of sleep by detecting a specified sound, and driving to undulate a floor plate part supported so as to be freely turnable by a bed frame, through a timer by a duration of a detecting output exceeding a level.

CONSTITUTION: A bed frame is constituted by connecting a head board 1 and a foot board 2 by a side frame 3, floor plates 4, 5 are extended horizontally between the frames 3, 3, and a mattress 6 is placed on the floor plates 4, 5. The floor plate 4 is supported between the frames 3, 3 so that it can be undurated at the board 1 side. A microphone 16 is provided in the board 1, and a snore is detected and converted to an electric signal. Detecting voltage is rectified and held 19 through an amplifier 17 and a BPF18. Timers 22aW22e are operated by continuation of a sound output exceeding a set level 20 and the floor plate 4 is displaced. In this way, a snore generated in the course of sleep is reduced, and also eliminated.