PURPOSE: To obtain the steel sheet pile with a joint which is not destroyed by the compaction of earth in a claw section, when the sheet pile is driven into ground, by local heat-processing a U-formed joint clad base section in a specified length from a penetration tip, and by increasing the strength thereof.

CONSTITUTION: The claw base section (n) of the joint section (c) of steel sheet piles A, B is heated at approx. 900°C in a specified length from a penetration tip and is oil-cooled, to enhance its strength. It is desirable that the length to be heated is approx. 50mm or more and 1,000mm or less. When the steel sheet pile B obtained as the result thereof is driven into ground along the previously set steel sheet pile A, then earth in claws engaged with each other is compacted at the lower section, but the strength of the joint claw base section (n) is kept enhanced, and so the joint section (c) is not destroyed by the compaction of earth.