1 . A loop-type heat pipe comprising: an evaporator configured to vaporize a working fluid; a condenser configured to condense the working fluid; a liquid pipe configured to connect the evaporator and the condenser to each other; a vapor pipe configured to connect the evaporator and the condenser to each other; and a loop-shaped flow channel extending through each of the evaporator, the condenser, the liquid pipe, and the vapor pipe, and through which the working fluid flows, wherein at least one of the evaporator, the condenser, the liquid pipe, and the vapor pipe comprises: 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, wherein the porous body comprises: a plurality of first bottomed holes provided in the first inner surface, a plurality of second bottomed holes provided in the second inner surface, a fine pore, wherein one first bottomed hole of the plurality of first bottomed holes and one second bottomed hole of the plurality of second bottomed holes partially communicate with each other through the fine pore, a first groove portion provided in the first inner surface and configured to communicate with two or more first bottomed holes of the plurality of first bottomed holes, and a second groove portion provided in the second inner surface and configured to communicate with two or more second bottomed holes of the plurality of second bottomed holes, wherein the first groove portion and the second groove portion do not overlap each other in a plan view, the first metal layer and the second metal layer are the only metal layers of the at least one of the evaporator, the condenser, the liquid pipe, and the vapor pipe, and the second inner surface is directly bonded to the first inner surface.
2 . The loop-type heat pipe according to claim 1 , wherein the plurality of first bottomed holes are provided side by side along a first direction and are provided side by side along a second direction intersecting the first direction, wherein the plurality of second bottomed holes are provided side by side along the first direction and are provided side by side along the second direction, wherein the first groove portion extends along the first direction, and wherein the second groove portion extends along the first direction.
3 . The loop-type heat pipe according to claim 2 , wherein the plurality of first bottomed holes are aligned in a grid shape in the plan view, wherein the plurality of second bottomed holes are aligned in a grid shape in the plan view and are provided at positions offset from the first bottomed holes in the second direction, wherein the first groove portion does not overlap the second bottomed hole in the plan view, and wherein the second groove portion does not overlap the first bottomed hole in the plan view.