To facilitate foreign substance evacuation from each lamp chamber by the air even for a lamp device provided with an amber cap by forming a clearance between a tip of a partition to partition a space inside a housing into two lamp chambers vertically adjacent to each other and an outer lens, and by forming a vent hole in the side face of the amber cap.

A front combination lamp L has a vertical two-stage structure composed of a turn signal lamp 1 and a clearance lamp 2, and the inside space of a housing 6 provided with an outer lens 5 on its front face is partitioned into two lamp chambers 8, 9 by a nearly horizontal partition 7. Openings 10, 11 are formed in the back walls of the lamp chambers 8, 9, respectively. An amber cap 13 is installed on the opening 10, and a bulb is mounted in its inside. A vent hole 15 is formed in the amber cap 13. A clearance S having a fine distance is formed between a tip of a rib 12 of the partition 7 and the inside face of the outer lens 5. Thereby, an air flow entering from the opening 10 and going out of the opening 11 can be formed so that foreign substances present in the lamp chambers 8, 9 can be exhausted.