An evaporator includes a first metal layer having a first inner surface and a first outer surface, a second metal layer having a second inner surface bonded to the first inner surface and a second outer surface, and a porous body provided between the first outer surface and the second outer surface. The porous body includes first bottomed holes provided in the first inner surface, second bottomed holes provided in the second inner surface, a fine pore, a first groove portion provided in the first inner surface, and a second groove portion provided in the second inner surface. The first groove portion and the second groove portion are provided not to overlap each other in a plan view. The first outer surface and the second outer surface serve as an outer surface of the evaporator.