A lamp unit for a vehicle headlamp includes a projection lens disposed on an optical axis extending in a longitudinal direction of a vehicle and a plurality of light source units disposed rearwards of a rear focal plane of the projection lens. Each of the light source units includes a light emitting device; and a light guiding member having a front end light output port and adapted to guide light from the light emitting device to the front end light output port so as to allow the light be emitted from the front end light output port. The front end light output ports of the light guiding members of the respective light source units are arranged adjacent to each other in a horizontal direction in a vicinity of the rear focal plane.