The disclosure facilitates determining the presence of an abnormality of a light source in a vehicular lamp using, as a determination condition, a number of disconnected semiconductor light-emitting elements among multiple semiconductor light-emitting elements. The vehicular lamp includes a first light source block that has light-emitting diodes LED1 to LED6 connected in parallel; a second light source block that has light-emitting diodes LED7 to LED12 connected in parallel; and an abnormality determination circuit that controls a supply of current from an on-board battery to the light source blocks and determines whether an abnormality is presence in the light source blocks. The abnormality determination circuit determines the presence of an abnormality if the disconnected light-emitting diodes in one of the light source blocks exceed a predetermined number and current cannot flow to the light source block. In such case, the supply of current to the light source blocks is stopped.