Light source and vehicle lamp

A light source for vehicles can include a base (20) having a cavity formed on its upper surface, an LED chip mounted in the cavity (20a) of the base, a resin portion for sealing the LED chip (21) in the cavity (20a), an optical member (23) disposed above the base (20) and apart from the LED chip (21), a light shielding portion (24) disposed on the inner surface of the optical member (23) and which forms a cutoff suited for a light distribution pattern, and a fluorescent substance layer (25) disposed at least in regions other than the light shielding portion (24) on the inner surface of the optical member (23).