An intake manifold, comprising: a base member and a cover member, respectively made of resin and extending along an intake passage, the base member and the cover member facing each other in radial direction of the intake passage; and a flame damper having a flame suppression structure, the flame damper incorporated in a one end side portion of the base member to be positioned on the intake passage, wherein the one end side portion of the base member includes a recessed body portion having a split cylindrical shape and a fitting holding portion integrally formed with the recessed body portion to hold the flame damper by fitting the flame damper in axial direction to abut against the fitting holding portion, the fitting holding portion includes an abutment surface against which the flame damper abuts from the side of the recessed body portion, and a fitting inner peripheral wall surface that surrounds and fits the flame damper therein, the flame damper is constituted by the flame suppression structure, an outer cylindrical body that surrounds an outer periphery of the flame suppression structure, characterized in that the flame damper is further constituted by an elastic holder member that covers an outer peripheral surface of the outer cylindrical body and both end surfaces (27b, 27c) of the outer cylindrical body, the elastic holder member includes an outer peripheral fitting portion including a cylindrical wall portion held in close contact with the outer peripheral surface of the outer cylindrical body and fitted to the fitting holding portion, and a plurality of annular lip portions (52a, 52b, 52c) respectively protruding from an outer peripheral surface of the cylindrical wall portion diagonally to the outside in radial direction and downstream side in axial direction while being spaced apart from each other in axial direction, the elastic holder member having an abutment portion on one side and an abutment portion on the other side arranged integrally with the outer peripheral fitting portion, the abutment portion on one side is arranged to be abutted to engage with the abutment surface, having an annular plate shape, of the fitting holding portion while surrounding an opening on an end side of the flame suppression structure, the abutment portion on the other side is arranged to be pressed in a retaining direction by a retaining rectifying member while surrounding an opening on the other side of the flame suppression structure. a base member and a cover member, respectively made of resin and extending along an intake passage, the base member and the cover member facing each other in radial direction of the intake passage; and a flame damper having a flame suppression structure, the flame damper incorporated in a one end side portion of the base member to be positioned on the intake passage, wherein the one end side portion of the base member includes a recessed body portion having a split cylindrical shape and a fitting holding portion integrally formed with the recessed body portion to hold the flame damper by fitting the flame damper in axial direction to abut against the fitting holding portion, the fitting holding portion includes an abutment surface against which the flame damper abuts from the side of the recessed body portion, and a fitting inner peripheral wall surface that surrounds and fits the flame damper therein, the flame damper is constituted by the flame suppression structure, an outer cylindrical body that surrounds an outer periphery of the flame suppression structure, characterized in that the flame damper is further constituted by an elastic holder member that covers an outer peripheral surface of the outer cylindrical body and both end surfaces (27b, 27c) of the outer cylindrical body, the elastic holder member includes an outer peripheral fitting portion including a cylindrical wall portion held in close contact with the outer peripheral surface of the outer cylindrical body and fitted to the fitting holding portion, and a plurality of annular lip portions (52a, 52b, 52c) respectively protruding from an outer peripheral surface of the cylindrical wall portion diagonally to the outside in radial direction and downstream side in axial direction while being spaced apart from each other in axial direction, the elastic holder member having an abutment portion on one side and an abutment portion on the other side arranged integrally with the outer peripheral fitting portion, the abutment portion on one side is arranged to be abutted to engage with the abutment surface, having an annular plate shape, of the fitting holding portion while surrounding an opening on an end side of the flame suppression structure, the abutment portion on the other side is arranged to be pressed in a retaining direction by a retaining rectifying member while surrounding an opening on the other side of the flame suppression structure.