PURPOSE: To prevent deterioration in a support force, by a method wherein a stiffener formed by a rigid material is buried in the interior of a friction pile, made of a light material, along the direction of the axis of the friction pile.

CONSTITUTION: A friction pile 1, formed by a light material, such as rigid foamed polyurethane, and a stiffener 2 with load dispersion bodies 21, made of a metallic material, such as carbon steel, having high rigidity, is buried in the interior of the pile 1. Thus, as compared with a conventional concrete pile, the titled pile is decreased in weight, enables prevention of a deterioration in a support force due to an increase in its own weight, and permits increase of a load support force.