To provide a high-luminance light source having high emitted-light extraction efficiency; and to provide a vehicular lamp using the light source.

This vehicular lamp 1 is provided with a light source unit 30 comprising: a nearly cylindrical positive electrode 42; a negative electrode 44 disposed separately on the side of an inner-diameter surface 42c of the positive electrode 42; and a phosphor 46 formed on the positive electrode 42 and formed of a fluorescent substance. Electrons are emitted from the negative electrode 44, and the electrons are accelerated toward the positive electrode 42 and collide with the phosphor 46. The electrons emit light by exciting the fluorescent substance of the phosphor 46. The emitted light is reflected by a reflecting surface 20a of a reflector 20 and emitted in a predetermined direction.