A vehicular lamp comprising: a plurality of light source portions ; a circuit board ; and a lighting circuit including a DC-DC converter configured to drive the plurality of light source portions , wherein the DC-DC converter including a plurality of converter portions , each of which includes a switching circuit portion and a control circuit portion , the switching circuit portion being configured to obtain an output voltage by stepping up or stepping down an input voltage with a switching converter circuit including a switch element (T1, T51), a wound element (L1, L51), and a rectifier element (D1, D51), and the control circuit portion being configured to control the output voltage by controlling the switch element (T1, T51) of the switching circuit portion , the DC-DC converter including as the plurality of converter portions a first converter portion including a first switching circuit portion and a first control circuit portion , and a second converter portion including a second switching circuit portion and a second control circuit portion , the vehicular lamp being characterized in that the plurality of converter portions are mounted on the circuit board ; the first switching circuit portion , the first control circuit portion , the second control circuit portion , and the second switching circuit portion are arranged lined up in order of the first switching circuit portion , the first control circuit portion , the second control circuit portion , and the second switching circuit portion in one direction on the circuit board ; and the first switching circuit portion and the second switching circuit portion are positioned at ends of the circuit board . a plurality of light source portions ; a circuit board ; and a lighting circuit including a DC-DC converter configured to drive the plurality of light source portions , wherein the DC-DC converter including a plurality of converter portions , each of which includes a switching circuit portion and a control circuit portion , the switching circuit portion being configured to obtain an output voltage by stepping up or stepping down an input voltage with a switching converter circuit including a switch element (T1, T51), a wound element (L1, L51), and a rectifier element (D1, D51), and the control circuit portion being configured to control the output voltage by controlling the switch element (T1, T51) of the switching circuit portion , the DC-DC converter including as the plurality of converter portions a first converter portion including a first switching circuit portion and a first control circuit portion , and a second converter portion including a second switching circuit portion and a second control circuit portion , the vehicular lamp being characterized in that the plurality of converter portions are mounted on the circuit board ; the first switching circuit portion , the first control circuit portion , the second control circuit portion , and the second switching circuit portion are arranged lined up in order of the first switching circuit portion , the first control circuit portion , the second control circuit portion , and the second switching circuit portion in one direction on the circuit board ; and the first switching circuit portion and the second switching circuit portion are positioned at ends of the circuit board . <EOS>