To provide an apparatus or a method for determining a walking state constituted to detect shaking of a posture such as stumbling in an early stage and generate an assisting power for recovering the posture before largely losing the balance of the posture.

This apparatus for determining walking state is provided with a sensor 21 disposed on a human body to measure the tension of the muscle for detecting that the posture in walking becomes unstable, a differentiation means 25 differentiating an output value of the sensor, a comparison means 26 comparing the output of the differentiation means with a preset determination value, and a determination means 28 determining that the posture of the user becomes unstable, when the output of the differentiation means exceeds the determination value. This apparatus determines the unbalance by differentiating the output value of the muscle tension measuring sensor and comparing the differentiation value with the preset determination value.