A walking assist device is capable of operating at an appropriate cycle in view of the motion cycle of a human being to be assisted while at the same time reducing the number of control parameters to be adjusted or set. A second phase oscillator, based on which the phase of the periodic operation of each actuator is controlled, is calculated on the basis of the difference between a first phase oscillator, which indicates a phase of the periodic motion of each thigh relative to the upper body of a human being, and the second phase oscillator, and an intrinsic angular velocity. A current intrinsic angular velocity is set by correcting a previous intrinsic angular velocity by an amount based on a previous difference between the first phase oscillator and the second phase oscillator such that the previous difference approaches a desired difference.
