To securely and rapidly crush concrete of an inferior part near the top end without noise and vibration and reduce the construction period.

In the removing method of a defective finish part D formed near a concrete C top end after the concrete C has been placed in a hole or a ditch excavated in the ground E and cured, one or more bar-shaped bodies 14 having a length corresponding to the thickness of the inferior part expected before the concrete C is placed or cured are driven from the top end of the concrete C. After it has been cured, the bar-shaped bodies 14 are drawn to form a hole 16. An expansive agent 18 us poured in the hole to give a static pressure toward the outside to the inner wall of the hole. In this way, the concrete C at the periphery of the hole 16 is crushed and removed.