A vehicular luminaire comprising: a socket formed of a highly heat-conductive material, which is electrically conductive, a light-emitting module, and a power-supply unit, wherein the socket comprises; a mounting portion, a bayonet adapted for mounting the vehicular luminaire on a housing of a vehicular lamp, a flange, and at least one thermal radiation fin provided on a side that is opposite to a mounting portion side of the flange; wherein the mounting portion, the at least one thermal radiation fin, the bayonet, and the flange are molded integrally; wherein the mounting portion has a recessed portion, which is open to an end face that is on a side which is opposite to the flange side, wherein the light-emitting module is provided on a bottom surface (11a1) of the recessed portion, the vehicular luminaire further comprising: a substrate being part of the light-emitting module and provided on the socket and including a wiring pattern on at least one surface; at least one light-emitting element being part of the light-emitting module and electrically connected to the wiring pattern; a plurality of power-supply terminals extending inside the socket and each including one end portion exposed from the socket, a vicinity of the end portion being bent toward the substrate, the end portion being provided on a surface of the substrate on a side where the light-emitting element is provided or a surface of the substrate on a side opposite to the side where the light-emitting element is provided; an insulating portion provided in a space between the plurality of end portions; an insulating portion provided in a space between the plurality of end portions and the mounting portion; and an insulating portion that provides covering between the plurality of end portions and between the plurality of end portions and the mounting portion. a socket formed of a highly heat-conductive material, which is electrically conductive, a light-emitting module, and a power-supply unit, wherein the socket comprises; a mounting portion, a bayonet adapted for mounting the vehicular luminaire on a housing of a vehicular lamp, a flange, and at least one thermal radiation fin provided on a side that is opposite to a mounting portion side of the flange; wherein the mounting portion, the at least one thermal radiation fin, the bayonet, and the flange are molded integrally; wherein the mounting portion has a recessed portion, which is open to an end face that is on a side which is opposite to the flange side, wherein the light-emitting module is provided on a bottom surface (11a1) of the recessed portion, the vehicular luminaire further comprising: a substrate being part of the light-emitting module and provided on the socket and including a wiring pattern on at least one surface; at least one light-emitting element being part of the light-emitting module and electrically connected to the wiring pattern; a plurality of power-supply terminals extending inside the socket and each including one end portion exposed from the socket, a vicinity of the end portion being bent toward the substrate, the end portion being provided on a surface of the substrate on a side where the light-emitting element is provided or a surface of the substrate on a side opposite to the side where the light-emitting element is provided; an insulating portion provided in a space between the plurality of end portions; an insulating portion provided in a space between the plurality of end portions and the mounting portion; and an insulating portion that provides covering between the plurality of end portions and between the plurality of end portions and the mounting portion. a substrate being part of the light-emitting module and provided on the socket and including a wiring pattern on at least one surface; at least one light-emitting element being part of the light-emitting module and electrically connected to the wiring pattern; a plurality of power-supply terminals extending inside the socket and each including one end portion exposed from the socket, a vicinity of the end portion being bent toward the substrate, the end portion being provided on a surface of the substrate on a side where the light-emitting element is provided or a surface of the substrate on a side opposite to the side where the light-emitting element is provided; an insulating portion provided in a space between the plurality of end portions; an insulating portion provided in a space between the plurality of end portions and the mounting portion; and an insulating portion that provides covering between the plurality of end portions and between the plurality of end portions and the mounting portion.