side face of the fitting portion 482 of the brake shoe 148 is pressed against a side face of the groove within the sub rail 166 resulting in that a frictional force between the two increases since this increase in frictional force inhibits movement of the slider 142 the vertical arm portion 104 cannot move a pulling force of a pushing force acts in arrow a direction on the horizontal arm portion 102 when the patient grasps the horizontal arm 102 however in such a case movement of the vertical arm portion 104 is inhibited as above and the patient supporting apparatus 10 is sure to be held in position the portion comprising the sub rail 166 and the brake shoe 148 is an example of the brake defined in the present invention the sub rail 166 is an example of the sub rail defined in the present invention the brake shoe 148 is an example of the brake shoe defined in the present invention the gear 504 is an example of the drive gear defined in the present invention the gear 484 is an example of the driven gear defined in the present invention since the brake includes the sub rail 166 parallel to the main rail 164 and the brake shoe 148 adapted to be pushed against the sub rail by utilizing a moment of rotation it is possible to simplify its construction since the sub rail 166 is a grooved rail it is possible to simplify the structure of the brake shoe since the brake shoe 148 has the fitting portion 482 for.