A torque testing device includes a base, a clamping device for clamping a fastener, a holing cylinder mounted on the base, a mounting beam mounted on the holding cylinder, a moving component, a rotation component, and a torque wrench. The mounting beam defines a nesting hole. The moving component includes a tubular member received in the nesting hole and a driving component mounted on the mounting beam for driving the tubular member towards the fastener. The rotation component includes a rotation shaft and at least one rotation element positioned between the rotation shaft and the tubular member. The rotation shaft is moved with the tubular member towards the fastener. The rotation shaft is capable of being rotated about the tubular member through the rotation element. The torque wrench is connected to the rotation shaft for applying torque to the rotation shaft and revealing the value of the torque.