A lamp for a vehicle, comprising: a cover lens; a housing coupled to the cover lens to form a space; a light output unit disposed in the space and comprising a plurality of light generation groups arranged in a first direction in the space; and a light guide comprising a plurality of optical branches (1010, 1020, 1030, 1040, 1050) extending in a second direction inside the space, wherein the second direction forms a specific angle relative to the first direction, wherein a number of the plurality of optical branches (1010, 1020, 1030, 1040, 1050) corresponds to a number of the plurality of light generation groups, and wherein the plurality of optical branches (1010, 1020, 1030, 1040, 1050) is stacked in the first direction, characterized in that each of the plurality of optical branches (1010, 1020, 1030, 1040, 1050) comprises one or more optical patterns (1011, 1021, 1031, 1041, 1051) placed at different locations with respect to the second direction, and wherein the optical patterns (1011, 1021, 1031, 1041, 1051) are arranged in a way that a first optical pattern of a first optical branch is extending in the second direction, and a second optical pattern of a second optical branch is extending from one end of the first optical pattern in the second direction, and wherein in proportion to a distance (1810, 1820) of the respective light generation group (1110, 1120, 1130, 1140, 1150) from the cover lens each of the plurality of light generating groups (1110, 1120, 1130, 1140, 1150) generates a different amount of light, whereby the farther the respective light generation group (1110, 1120, 1130, 1140, 1150) is disposed from the cover lens, the greater amount of light is stably output to the outside by the corresponding light generation group (1110, 1120, 1130, 1140, 1150). a cover lens; a housing coupled to the cover lens to form a space; a light output unit disposed in the space and comprising a plurality of light generation groups arranged in a first direction in the space; and a light guide comprising a plurality of optical branches (1010, 1020, 1030, 1040, 1050) extending in a second direction inside the space, wherein the second direction forms a specific angle relative to the first direction, wherein a number of the plurality of optical branches (1010, 1020, 1030, 1040, 1050) corresponds to a number of the plurality of light generation groups, and wherein the plurality of optical branches (1010, 1020, 1030, 1040, 1050) is stacked in the first direction, characterized in that each of the plurality of optical branches (1010, 1020, 1030, 1040, 1050) comprises one or more optical patterns (1011, 1021, 1031, 1041, 1051) placed at different locations with respect to the second direction, and wherein the optical patterns (1011, 1021, 1031, 1041, 1051) are arranged in a way that a first optical pattern of a first optical branch is extending in the second direction, and a second optical pattern of a second optical branch is extending from one end of the first optical pattern in the second direction, and wherein in proportion to a distance (1810, 1820) of the respective light generation group (1110, 1120, 1130, 1140, 1150) from the cover lens each of the plurality of light generating groups (1110, 1120, 1130, 1140, 1150) generates a different amount of light, whereby the farther the respective light generation group (1110, 1120, 1130, 1140, 1150) is disposed from the cover lens, the greater amount of light is stably output to the outside by the corresponding light generation group (1110, 1120, 1130, 1140, 1150).