A loop heat pipe includes two outermost metal layers, an intermediate metal layer provided between the outermost metal layers, an evaporator, a condenser, and liquid and vapor pipes connecting the evaporator and the condenser and forming a loop shaped passage. The intermediate metal layer includes a pair of walls forming a part of a pipe wall of the evaporator, the condenser, the liquid pipe, and the vapor pipe, a porous body provided between the pair of walls, and a strut penetrating the porous body and bonding the outermost metal layers, and one or more metal layers. Each of the one or more metal layers includes a first part forming a part of the pair of walls, a second part connected to the first part and forming a part of the porous body, and a third part connected to the second part and forming a part of the strut.