VEHICULAR LIGHTING FIXTURE

To provide a vehicular lighting fixture that can inhibit a crack from being generated in a socket for installing a light source part.SOLUTION: A vehicular lighting fixture (100) includes: a light source part (20) including a light-emitting device and a circuit board; and a socket part (10) for installing the light source part (20). In the vehicular lighting fixture (100), the socket part (10) includes: a housing made of a heat conductive resin; and a metal plate embedded into the housing. The metal plate is partially exposed from the housing and connected to the light source part (20) so as to be capable of conducting heat. The heat conductive resin has a linear expansion coefficient in a flowing direction (MD direction) of 10×10-6/K or more and 30×10-6/K or less and a linear expansion coefficient in a flow vertical direction (TD direction) of 30×10-6/K or more and 80×10-6/K or less.SELECTED DRAWING: Figure 1 【課題】光源部を搭載するソケットにおけるクラックの発生を抑制できる、車両用灯具を提供する。【解決手段】発光素子および回路基板を有する光源部（２０）と、光源部（２０）を搭載するソケット部（１０）と、を備える車両用灯具（１００）であって、ソケット部（１０）は、熱伝導性樹脂から構成されるハウジングと、ハウジングに埋め込まれた金属板と、を有し、金属板は、ハウジングから部分的に露出して、熱伝導可能に光源部（２０）と接続されており、熱伝導性樹脂が、１０×１０－６／Ｋ以上３０×１０－６／Ｋ以下の流動方向（ＭＤ方向）の線膨張係数および３０×１０－６／Ｋ以上８０×１０－６／Ｋ以下の流動垂直方向（ＴＤ方向）の線膨張係数を備える、車両用灯具（１００）。【選択図】図１