A loop heat pipe includes an evaporator, a condenser, a liquid pipe, and a vapor pipe. The liquid pipe is formed a metal layer stack of metal layers. The metal layers include a first metal layer through which a first through hole extends in a thickness-wise direction. The liquid pipe includes a flow passage formed by at least the first through hole and having four walls that define the flow passage. The liquid pipe further includes a plurality of porous bodies that form at least two of the four walls of the flow passage.