PURPOSE: To connect two adjacent steel sheet piles definitely and promptly and prevent the piles from dropping together in terms of a steel sheet pile joint.

CONSTITUTION: A first hydraulic clamp 1 and a second hydraulic clamp 2 are used, which are operated with hydraulic pressure provided from a hydraulic device 5 by way of a hydraulic hose 6. The second hydraulic clamp 2 is used to clamp the upper end of a flange of a steel sheet pile 7a which may be subject to mutual sinking while the first hydraulic clamp is used to clamp the upper end of a flange of a steel sheet pile 7b, thereby connecting both the steel sheet piles 7a and 7b. Therefore, the steel sheet pile 7b can serve as a reaction force receiving steel sheet pile while the steel sheet pile 7a can resist against tensile force produced by a mutual sinking phenomenon.