To provide a leg muscle strengthener capable of being safely used by users ranging from a healthy user to the elderly whose muscles are weakened so that walking is hard, and capable of easily training muscles in both legs according to the physical strength of users to strengthen the muscles.

The leg muscle strengthener consists of a mat 2 on which a user puts the buttocks, left and right leg stretching spring bodies 3 whose rear ends are fixed to prescribed positions near the front edge of the mat 2, and ankle fixtures 4 which are fixed to the distal ends of the respective leg stretching spring bodies 3 and which can be attached to/detached from the ankles of the user. It is preferable to use strap-like elastic rubber bodies with elastic coated layers as the left/right leg stretching spring bodies 3. The rear end of each left or right leg stretching spring body is fixed to the front edge of the mat via a connectible/detachable implement.