PURPOSE: To obtain a friction pile which does not sink even in weak ground by forming the inner core part of the pile from a light-weight material such as foam polystyrene, etc., and forming the outer shell part from a hard material such as reinforced concrete, FRP, etc.

CONSTITUTION: An inner core part 1 is made of a light-weight material such as foam polystyrene, etc. An outer shell part 2 for covering the inner core part 1 is made of a hard material such as reinforced concrete, FRP, etc. Further, friction plates, resistance plates are attached to the outer shell part 2 as required. A friction pile which operates efficiently even in weak ground can thus be obtained.