To provide a lower-limb stabilizing device which prevents the lower limbs from rotating outward in the lateral direction, by supporting the entire lower limb by a bottom mattress or the like, in a planar state during sleep in a supine position, and which has a simple structure.

The lower-limb stabilizing device 10 is equipped with a cylindrical knee pad 12 which is a bandage containing rubber and is wound around a knee part of the lower limb, a knee-stabilizing device 11 which is attached to the knee pad 12 and comprises a knee-supporting part 13 to fill the recess on the back of the knee, an ankle pad 16 which is a bandage containing rubber that is wound around the ankle and is an L-shaped cylinder with a notched heel part, and an ankle-stabilizing device 15 which is attached to the ankle pad 16 and comprises an ankle-supporting part 17 to fill a recess on the back of the ankle. The knee-supporting part 13 and the ankle-supporting part 17 have elasticity, by filling cotton or the like in the bag part made of a fabric in a compressed state so as to keep shape-retaining properties and have less deformation.