To facilitate a method for building up muscle by providing a device which can inhibit blood from circulating through muscles, which can vary a compressive force imparted to the muscles while the force is accurately grasped, and which allows to exercise with the device attached to the body.

A means for measuring a compressive force of the muscle buildup device is constituted of a pressure-sensitive element 13 connected to an indicator 17, a pressure bag 3 provided in an inflatable cuff 1, and a transmitting means for pressurizing the element 13 in accordance with the pressure received from inside the pressure bag. A tightening pressure imparted to the muscle by the inflatable cuff 1 is measured through the air inside the pressure bag 3; therefore, it is possible to measure the pressure more accurately regardless of the condition of the muscle to be developed, e.g. the presence/absence of clothing or the quantity of fats.