一种生理信号传感系统、生理信号截取设备与可抛式设备。生理信号传感系统包括可抛式设备与生理信号截取设备。可抛式设备包括弹性限位件与可动式固定器。生理信号截取设备包括突出结构。可动式固定器可组装于弹性限位件上，可用来将弹性限位件限制在屈曲状态。在可抛式设备第一次与生理信号截取设备的组装过程中，上述突出结构会触动可动式固定器脱离弹性限位件。另外，可抛式设备与生理信号截取设备解组装之后，弹性限位件会由屈曲状态转换到展开状态借以阻挡可抛式设备再次组装于生理信号截取设备。

A vital sign sensing system, a vital sign obtaining device, and a disposable device are provided. The vital sign sensing system includes the vital sign obtaining device and the disposable device. The disposable device includes an elasticity stopper and a movable fastener. The vital sign obtaining device includes a protrusion structure. The movable fastener is assembled on the elasticity stopper so that the elasticity stopper is showed a flexion state. In a first procedure that the disposable device is assembled to the vital sign obtaining device, the movable fastener is uninstalled from the elasticity stopper by the protrusion structure, and the elasticity stopper is converted from the flexion state to an expansion state so as to prevent the disposable device be reused in vital sign obtaining device.