An exhaust pipe structure comprising: a first exhaust pipe extending along a first direction; a second exhaust pipe disposed downstream of the first exhaust pipe in an exhaust gas flow direction, the second exhaust pipe extending along a second direction, the second direction intersecting the first direction; an upstream end portion of the second exhaust pipe in an exhaust gas flow direction overlaps the first exhaust pipe such that a centre line of the first exhaust pipe intersects an outer peripheral surface of the second exhaust pipe; and a coupling member configured to couple the first exhaust pipe and the second exhaust pipe together, the coupling member having an opening, and an inside of the first exhaust pipe communicating with an inside of the second exhaust pipe via the opening, the coupling member including a first exhaust pipe joint portion and a bottom plate portion, wherein a downstream end portion of the first exhaust pipe in the exhaust gas flow direction is inserted into the first exhaust pipe joint portion, the bottom plate portion being disposed in an internal space of the first exhaust pipe joint portion and shaped so as to conform to the outer peripheral surface of the second exhaust pipe and to correspond to a region where the first exhaust pipe and the second exhaust pipe overlap each other as viewed from the first direction, the region being adjacent to the opening as viewed from the first direction, and the coupling member having a groove defined in a surface of the bottom plate portion, the surface of the bottom plate portion facing the inside of the first exhaust pipe, and the groove extending along an outer edge portion of the bottom plate portion toward the opening. a first exhaust pipe extending along a first direction; a second exhaust pipe disposed downstream of the first exhaust pipe in an exhaust gas flow direction, the second exhaust pipe extending along a second direction, the second direction intersecting the first direction; an upstream end portion of the second exhaust pipe in an exhaust gas flow direction overlaps the first exhaust pipe such that a centre line of the first exhaust pipe intersects an outer peripheral surface of the second exhaust pipe; and a coupling member configured to couple the first exhaust pipe and the second exhaust pipe together, the coupling member having an opening, and an inside of the first exhaust pipe communicating with an inside of the second exhaust pipe via the opening, the coupling member including a first exhaust pipe joint portion and a bottom plate portion, wherein a downstream end portion of the first exhaust pipe in the exhaust gas flow direction is inserted into the first exhaust pipe joint portion, the bottom plate portion being disposed in an internal space of the first exhaust pipe joint portion and shaped so as to conform to the outer peripheral surface of the second exhaust pipe and to correspond to a region where the first exhaust pipe and the second exhaust pipe overlap each other as viewed from the first direction, the region being adjacent to the opening as viewed from the first direction, and the coupling member having a groove defined in a surface of the bottom plate portion, the surface of the bottom plate portion facing the inside of the first exhaust pipe, and the groove extending along an outer edge portion of the bottom plate portion toward the opening.