Abstract: To provide a muscle strength training apparatus with a simple structure and low production cost and a muscle strength training method, wherein the apparatus and the method are capable of conducting muscle strength training that acts on both flexion and extension with load decreasing when the muscle is fatigued, and are safe without excessive force being applied on joints or muscles because no load is applied when movement is stopped. [Solution] This muscle strength training apparatus is provided with a first fitted part (1) that is fitted along the femur of the user and a second fitted part (2) that is fitted along the lower leg of the user. The first fitted part (1) is pivotally attached to the second fitted part (2) by means of bolts (30a, 31a) and nuts (30b, 31b). The first fitted part (1) and the second fitted part (2) are connected via an oil damper (3). The oil damper (3) is disposed on the side opposite the side of lower leg flexion.