A one-touch pipe connection device comprising: a socket main body portion, wherein a plurality of pipe fitting portions, in each of which a pipe to be connected is inserted, are connected to each other; a sealing portion provided between the socket main body portion and the pipe to be connected and sealing between the pipe to be connected inserted in the pipe fitting portion and the socket main body portion; and a cap portion having a through hole therein for passing the pipe to be connected inserted in the pipe fitting portion, coupled to the pipe fitting portion while moving in an insertion direction of the pipe to be connected in the pipe fitting portion, and, when coupled to the pipe fitting portion, pressing the sealing portion in a direction in which the sealing portion closely contacts the pipe to be connected, wherein the sealing portion comprises a first sealing member that is provided at a side of an open entrance of the pipe fitting portion coupled to the cap portion and sealing between an inner circumferential surface of the pipe fitting portion and an outer circumferential surface of the pipe to be connected, wherein the cap portion comprises a pressure guide portion that induces flexural deformation of the first sealing member by pressing other side of the first sealing member in a lengthwise direction in the insertion direction when the cap portion moves in the insertion direction of the pipe to be connected characterized in that a guide support groove portion having a shape corresponding to a surface of an end portion of one side of the first sealing member in the lengthwise direction is formed at the side of the entrance of the pipe fitting portion toward an inner side of the pipe fitting portion in a lengthwise direction from the end portion of the entrance side of the pipe fitting portion, an inner support wall is formed at a side of the guide support groove portion adjacent to the inner circumferential surface of the pipe fitting portion, and an outer support wall is formed at a side of the guide support groove portion adjacent to an outer circumferential surface of the pipe fitting portion. a socket main body portion, wherein a plurality of pipe fitting portions, in each of which a pipe to be connected is inserted, are connected to each other; a sealing portion provided between the socket main body portion and the pipe to be connected and sealing between the pipe to be connected inserted in the pipe fitting portion and the socket main body portion; and a cap portion having a through hole therein for passing the pipe to be connected inserted in the pipe fitting portion, coupled to the pipe fitting portion while moving in an insertion direction of the pipe to be connected in the pipe fitting portion, and, when coupled to the pipe fitting portion, pressing the sealing portion in a direction in which the sealing portion closely contacts the pipe to be connected, wherein the sealing portion comprises a first sealing member that is provided at a side of an open entrance of the pipe fitting portion coupled to the cap portion and sealing between an inner circumferential surface of the pipe fitting portion and an outer circumferential surface of the pipe to be connected, wherein the cap portion comprises a pressure guide portion that induces flexural deformation of the first sealing member by pressing other side of the first sealing member in a lengthwise direction in the insertion direction when the cap portion moves in the insertion direction of the pipe to be connected characterized in that a guide support groove portion having a shape corresponding to a surface of an end portion of one side of the first sealing member in the lengthwise direction is formed at the side of the entrance of the pipe fitting portion toward an inner side of the pipe fitting portion in a lengthwise direction from the end portion of the entrance side of the pipe fitting portion, an inner support wall is formed at a side of the guide support groove portion adjacent to the inner circumferential surface of the pipe fitting portion, and an outer support wall is formed at a side of the guide support groove portion adjacent to an outer circumferential surface of the pipe fitting portion.