Various biomimetics had been analyzed and utilized in various fields. The muscle spindle is an invaluable displacement sensor in the living body. It is able to change resolution and to adjust sensitivity. In this paper, a new biomimetics tension sensor which has the characteristic muscle spindle and skeletal muscle structure and function was developed. The biomimetic tensiometer was created by fixing the piezo actuator as intrafusal muscle fiber mimetics and strain gauge. The muscle spindle mimetics consisted of the piezo actuator and the strain gauge and elastic component. The tensiometer utilized the muscle spindle mimetics and the skeletal muscle mimetics proportional variable length. Consequently a proportional variable length tensiometer was developed.