A pipe connection structure comprising: a first pipe member, a sealing portion of the first pipe member including a first abutment surface in a tapered shape, a diameter of the first abutment surface being increased toward a tip of the first pipe member, the sealing portion being configured to project radially inward from an inner wall surface of the first pipe member, and the inner wall surface being adjacent to the sealing portion; and a second pipe member, an end of the second pipe member including a second abutment surface in a tapered shape, a diameter of the second abutment surface being reduced toward a tip of the second pipe member, the second abutment surface abutting against the first abutment surface by being pressed, the first abutment surface and the second abutment surface abutting against each other at an abutment section, and the abutment section being located on a radially inner side of the inner wall surface of the first pipe member, wherein the first pipe member and the sealing portion are constructed as a single piece, and the sealing portion includes: a pressure receiving seat section including the first abutment surface and abutting against the second abutment surface; an apex section being a radially innermost section of the sealing portion, the apex section being adjacent to the pressure receiving seat section; and a joint section being adjacent to the apex section, the joint section being located on a side opposite to the pressure receiving seat section across the apex section, characterised in that the joint section has a tapered shape, a diameter of the joint section being increased in a direction away from the apex section. a first pipe member, a sealing portion of the first pipe member including a first abutment surface in a tapered shape, a diameter of the first abutment surface being increased toward a tip of the first pipe member, the sealing portion being configured to project radially inward from an inner wall surface of the first pipe member, and the inner wall surface being adjacent to the sealing portion; and a diameter of the first abutment surface being increased toward a tip of the first pipe member, the sealing portion being configured to project radially inward from an inner wall surface of the first pipe member, and the inner wall surface being adjacent to the sealing portion; and a second pipe member, an end of the second pipe member including a second abutment surface in a tapered shape, a diameter of the second abutment surface being reduced toward a tip of the second pipe member, the second abutment surface abutting against the first abutment surface by being pressed, the first abutment surface and the second abutment surface abutting against each other at an abutment section, and the abutment section being located on a radially inner side of the inner wall surface of the first pipe member, wherein an end of the second pipe member including a second abutment surface in a tapered shape, a diameter of the second abutment surface being reduced toward a tip of the second pipe member, the second abutment surface abutting against the first abutment surface by being pressed, the first abutment surface and the second abutment surface abutting against each other at an abutment section, and the abutment section being located on a radially inner side of the inner wall surface of the first pipe member, wherein the first pipe member and the sealing portion are constructed as a single piece, and the sealing portion includes: a pressure receiving seat section including the first abutment surface and abutting against the second abutment surface; an apex section being a radially innermost section of the sealing portion, the apex section being adjacent to the pressure receiving seat section; and a joint section being adjacent to the apex section, the joint section being located on a side opposite to the pressure receiving seat section across the apex section, a pressure receiving seat section including the first abutment surface and abutting against the second abutment surface; an apex section being a radially innermost section of the sealing portion, the apex section being adjacent to the pressure receiving seat section; and a joint section being adjacent to the apex section, the joint section being located on a side opposite to the pressure receiving seat section across the apex section, characterised in that the joint section has a tapered shape, a diameter of the joint section being increased in a direction away from the apex section.