A vehicular light source unit includes: an LED element integrated with a pair of plate-like feeding terminals; and an LED socket including a pair of plate spring-like conductive terminals in which movable portions and supporting portions that are integrally formed by a conductive member hold the pair of feeding terminals from both sides, and a resin housing integrated with the pair of conductive terminals. The LED element is detachably supported by the plate spring-like conductive terminals through the feeding terminals and receives a power supply from both sides of the feeding terminals.