A loop heat pipe comprising: a pair of outermost metal layers ; an intermediate metal layer (62-65) provided between the pair of outermost metal layers ; an evaporator configured to vaporize a working fluid to generate vapor; a condenser configured to liquefy the vapor of the working fluid; a liquid pipe connecting the evaporator and the condenser ; and a vapor pipe connecting the evaporator and the condenser , and forming a loop shaped passage together with the liquid pipe , characterized in that : the intermediate metal layer (62-65) 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 , a first strut penetrating the porous body and bonding the pair of outermost metal layers to each other, and one or a plurality of metal layers (62-65), wherein each of the one or plurality of metal layers (62-65) of the intermediate metal layer (62-65) includes a first part forming at least a part of the pair of walls , a second part connected to the first part , and forming at least a part of the porous body , and a third part connected to the second part , and forming at least a part of the first strut . a pair of outermost metal layers ; an intermediate metal layer (62-65) provided between the pair of outermost metal layers ; an evaporator configured to vaporize a working fluid to generate vapor; a condenser configured to liquefy the vapor of the working fluid; a liquid pipe connecting the evaporator and the condenser ; and a vapor pipe connecting the evaporator and the condenser , and forming a loop shaped passage together with the liquid pipe , characterized in that : the intermediate metal layer (62-65) 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 , a first strut penetrating the porous body and bonding the pair of outermost metal layers to each other, and one or a plurality of metal layers (62-65), wherein each of the one or plurality of metal layers (62-65) of the intermediate metal layer (62-65) includes a first part forming at least a part of the pair of walls , a second part connected to the first part , and forming at least a part of the porous body , and a third part connected to the second part , and forming at least a part of the first strut . the intermediate metal layer (62-65) 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 , a first strut penetrating the porous body and bonding the pair of outermost metal layers to each other, and one or a plurality of metal layers (62-65), 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 , a first strut penetrating the porous body and bonding the pair of outermost metal layers to each other, and one or a plurality of metal layers (62-65), wherein each of the one or plurality of metal layers (62-65) of the intermediate metal layer (62-65) includes a first part forming at least a part of the pair of walls , a second part connected to the first part , and forming at least a part of the porous body , and a third part connected to the second part , and forming at least a part of the first strut . a first part forming at least a part of the pair of walls , a second part connected to the first part , and forming at least a part of the porous body , and a third part connected to the second part , and forming at least a part of the first strut . <EOS>