A loop heat pipe includes an evaporator and a sealed pipe. The evaporator includes an evaporator body made of a heat conductive material. The evaporator body has at least two retaining holes and at least a channel hole penetrating the retaining holes. In addition, the sealed pipe includes at least two sealed ends. The two sealed ends are securely fastened to the two retaining holes of the evaporator. Meanwhile, at least one of the two retaining holes is a through hole, which penetrates through two sides of the evaporator body, and at least one of the sealed ends protrudes the evaporator via the penetrable retaining hole.