Loop heat pipe

A loop heat pipe comprising:

• an evaporator configured to vaporize a working fluid;
• a condenser configured to liquefy the working fluid;
• a liquid pipe configured to connect the evaporator and the condenser;
• and
• a vapor pipe configured to connect the evaporator and the condenser and form a loop-shaped passage,
• wherein the liquid pipe includes a first metal layer and a second metal layer forming outermost layers, and two or more metal layers that form inner layers stacked between the outer layers,
• wherein the inner layers are provided with one or more flow passages in which the working fluid flows, and a porous body communicating with the one or more flow passages,
• wherein a third metal layer forming the inner layers includes a first bottomed groove opening to a side of a fourth metal layer forming the inner layers and adjacent to the third metal layer,
• wherein the fourth metal layer includes a second bottomed groove opening to a side of the third metal layer, and
• wherein the one or more flow passages include a flow passage formed by the first bottomed groove and the second bottomed groove that are arranged to oppose and communicate with each other in a thickness direction.