A power steering apparatus has a first characteristic which is a characteristic of a command signal with respect to steering torque and a second characteristic which is a characteristic different from the first characteristic. When switching is to be made to a characteristic selected from between the first and second characteristics, an interpolation characteristic intermediate between the first and second characteristics is calculated so that the characteristic used before switching of the characteristics gradually approaches the characteristic to be used after the switching, and a characteristic switching time for switching between the first and second characteristics is variably controlled in accordance with the steering torque.