A tendon device for a suit type robot which includes: a first wire and a second wire respectively fixed on a front portion and a rear portion of a joint of a user, and moving in a lengthwise direction thereof according to flexion-extension of the joint; a tendon driver including a first tendon module including a first pulley, and a second tendon module including a second pulley; a first pulley encoder measuring a rotary angle of the first pulley; a second pulley encoder for measuring a rotary angle of the second pulley; a controller configured to calculate tensions of the first wire and the second wire based on the rotary angle of the first and second pulleys in order to generate a control signal; and a driver configured to provide the first tendon module and the second tendon module with a driving power.