This bed apparatus includes a bed frame, a floor plate body, a back-raising mechanism, an operating shaft, an attachment member, a transmission member, and a pressing member. The floor plate body includes a fixed floor part and a back floor part which has a center back part and a pair of side back parts that are connected to both sides of the center back part so as to rotate forward, and which is rotatable relative to the fixed floor part. The back-raising mechanism raises and lowers the back floor part. The operating shaft is rotatably supported by a back surface of the center back part. The attachment member is provided on an intermediate part of the operating shaft. The transmission member has one end fixed to the attachment member and another end fixed to a portion where tensile force is generated when the back floor part is driven in a rising direction, and causes the operating shaft to rotate by this tensile force. The pressing member is provided on both ends of the operating shaft such that the angle thereof can be changed, and is positioned in either an operating position at which the pair of side back parts are caused to rotate forward when the operating shaft is rotated by the transmission member or a non-operating position at which the pair of side back parts are not caused to rotate forward.La présente invention concerne un appareil de type lit comprenant un cadre de lit, un corps de plaque de plancher, un mécanisme d'élévation de dos, un arbre d'actionnement, un élément de fixation, un élément de transmission et un élément de pression. Le corps de plaque de plancher comprend une partie plancher fixe et une partie plancher arrière qui a une partie arrière centrale et une paire de parties arrière latérales qui sont reliés aux deux côtés de la partie arrière centrale de façon à tourner vers l'avant, et qui est rotative par rapport à la partie plancher fixe. Le mécanisme d'élévation de dos élève et abaisse la partie plancher arrière. L'arbre d'actionnement
