To provide a tubular foundation capable of obtaining easy screwing work, having a structure for obtaining settlement strength after the construction and lightening preceeding excavation work or executing an application or the like to a narrow ground.

The tubular foundation is so constituted that a part of each of two semi-oval bottom plate pieces is fixed to the inside of the front end of a pipe body and, at the same time, the other part of each of the two semi- oval bottom plate pieces is separated from the front end of the pipe body to the semi-oval bottom plate pieces are arranged in a cross-shape. The tubular foundation is constituted that a pair of plate pieces are projected to the front end of the pipe body parallel with the axis of the pipe body and that each of a pair of plate pieces is connected to a separation part of each of the two semi-oval bottom plate pieces.