A tendon stretcher including a base seat and a support frame which is pivotally mounted on the base seat and can be swung. A leaning pad and a saddle are fixedly connected on the support frame. An upward extending upright stem is disposed at one end of the base seat. A top end of the upright stem has a seat body for pivotally connecting with an extension bar. The bottom section of the seat body has an extending stop face. In addition, the seat body has a stop wall. A resilient body is disposed under the bottom of the extension bar corresponding to the stop face for abutting against the stop face. A pad body is disposed on one side of the extension bar corresponding to the stop wall for leaning against inner side of the stop wall.