The present invention relates to a top PHC piles (1) and the lower PHC piles (2) the upper plate and the lower plate and the cylindrical and PHC pole file formed by the plurality of gussets radially welded to joint device (3), PHC piles to a an end coupling device to the end, but coupling the PC steel bar (5) and the joints (3), end the coupling device is equal to or smaller than the outer diameter of the larger than the hollow inner diameter of the PHC piles or the same size as the inner diameter and the PHC piles forming a plurality of engaging portions (a) which force the ring-like circular plate 11 to the PC steel rod connection 12 and the joints neighboring concatenated to the nut hole 13 for coupling with the outer diameter of the size at a set interval, and, PC steel bar connection 12 is semi-spherical having a slightly larger diameter than the depth and the spherical projections (5a) an outer diameter corresponding to a half of the ring-like disc (11) thickness to the ring-like circular plate 11 so that the seat is a spherical projection (5a) formed in the PC steel bar end side forms a seating portion (12c), the other side PC steel bar (5) of the body (5b) is formed a through-hole (12d) having a diameter which can be through-nut hole 13 are joints (3) being firmly bonded, and formed to have a size with a spherical projection (5a) formed on the PC steel bar ends can be penetrated, PC steel rod connection 12 and the nut hole 13 is semi-spherical seating portion (12c) and a nut hole sikidoe concatenating an outer diameter of 13, the invention relates to a coupling device of a PC steel bar ends (5) of the PHC piles characterized in that the body is formed by connecting to a passage (12e) that can pass through.