A headlamp device for use in a leaning vehicle, including at least one headlamp that emits light in a front direction, and a pair of cornering lamps that emit light to form left-front and right-front light emission areas. Each of the at least one headlamp includes at least one headlamp light source, and a headlamp housing that stores the at least one headlamp light source and that is arranged inside the front cover. Each cornering lamp includes at least one cornering lamp light source, a light travel direction changing member having a light travel direction changing surface that changes a travel direction of light outputted from the at least one cornering lamp light source, and a cornering lamp housing that stores therein the at least one cornering lamp light source and the light travel direction changing member, and that is arranged inside the front cover. The cornering lamp housing and the headlamp housing are separate from each other.