Abstract: The invention provides a pile construction method which allows repeated formation of a supplemental base concrete body at the bottom of a cast-in-place pile, wherein before a previously introduced cement mortar consolidates at the bottom of the pile, a soil stabilizing liquid agent is injected through an injection tube which extends to the bottom of a pile so as to penetrate into the earth surrounding the bottom of the pile. After the cement mortar consolidates, the flow passages of the soil stabilizing agent become permanent passages in the pile base for a next injection of cement mortar.