Provided is a mechanism that is for predicting/detecting arising from bed and that can prevent accidents of falling from a bed without imparting a psychological burden or bodily restraints on a bedridden patient. The present invention is provided with: separate piezoelectric sensors (3a, 3b) that generate an electric charge in accordance with the load incurred from a bed (2) on which a human body (1) is carried a charge amplifier (4) and a computation control device (5). The motion path (A) of the center of gravity of a human body on the bed having a high likelihood of falling is stored ahead of time in the computation control device (5), the voltage output from the charge amplifier (4) is input to the computation control device (5), the center of gravity of the bed (2) on which the human body (1) is carried is computed on the basis of the voltage input to the computation control device (5), the motion path (B) traced by the center of gravity of the bed on which the human body is carried and changing by means of the movement of the human body (1) on the bed (2) and the motion path (A) stored ahead of time by the computation control device (5) are contrasted, and when the motion path (B) and the motion path (A) are similar or matching, a lamp (7) is lit and a buzzer (8) emits an alarm sound.Linvention concerne un mécanisme conçu pour prédire/détecter une chute de lit, et qui peut empêcher des accidents de chute de lit sans conférer de charge psychologique ni de contraintes corporelles sur un patient alité. La présente invention comprend : des capteurs piézoélectriques séparés (3a, 3b) qui génèrent une charge électrique en fonction de la charge soutenue par un lit (2) sur lequel se trouve un corps humain (1) un amplificateur de charge (4) et un dispositif de commande de calcul (5). La trajectoire de mouvement (A) du centre de gravité dun corps humain sur le lit ayant une forte probabilité de tomber est stockée à lavance dans le dispositif de commande de calcul (5),
