Load measuring parts 50 and 52 are provided with reaction sensors 50a, 50b, 52a and 52b to measure loads at two positions, the tiptoe and the heel, on each sole of right and left feet of a wearing person 12. The reaction sensor 50a detects a reaction force to a load on a front side of the right foot (right tiptoe), the reaction sensor 50b detects a reaction force to a load on a rear side of the right foot (right heel), the reaction sensor 52a detects a reaction force to a load on a front side of the left foot (left tiptoe), and the reaction sensor 52b detects a reaction force to a load on a rear side of the left foot (left heel). The reaction sensors 50a, 50b, 52a and 52b are arranged to detect, based on a change of a capacitance, the loads on the right and left feet during a walk action. A change of the load accompanied with a shift of the weight and a contact between the wearing person's foot and the ground can be detected.