To provide a sound sleep bed which aids the user to easily turn during the sleep.

The floor board is divided into a head part section 10, an upper half body section 20 and a lower half body section 30 in the longitudinal direction. Each section of the floor board is make up of three floor plates connected together horizontally with hinges. The central floor plate of the head part section 10 and the central floor plate of the upper half body section 20 and the central floor plate of the upper half body section 20 and the central floor plate of the lower half body section 30 are linked together respectively with a play so that the former floor plates move in delay relative to the latter floor plates. The central floor plates of the respective sections are rotatably pivoted with a shaft 41 while each of the central floor plates of the respective sections is provided with a coil spring so as to be kept horizontal by the energizing forces under no load.