This connection structure is a connection structure between a steel pipe pile and a steel sleeve pipe disposed outside the steel pipe pile with a gap therebetween and includes a steel plate with outward projections having a plurality of outward projections and fixed to an outer peripheral surface of the steel pipe pile by a first weld portion; a steel plate with inward projections having a plurality of inward projections and fixed to an inner peripheral surface of the steel sleeve pipe by a second weld portion; and grout filled in the gap so as to bury at least the steel plate with outward projections and the steel plate with inward projections, wherein the plurality of outward projections is disposed at intervals in a vertical direction with respect to one another and extends over a circumferential direction of the steel pipe pile, and the plurality of inward projections is disposed at intervals in a vertical direction with respect to one another and extends over a circumferential direction of the steel sleeve pipe.
展开▼
