A method of manufacturing a cooling device using a heat pipe, the method comprising: a filling step in which a predetermined support member is filled inside a pipe to prevent deformation of the pipe by a pressure of a melt being injected into a cavity (43, 44) of a mold (41, 42) that is closable; a pipe seating step in which the pipe filled with the predetermined support member is seated in the cavity (43, 44); a melt injecting step in which the melt is injected into the cavity (43, 44) to surround the pipe; a cooling and withdrawing step in which the injected melt is cooled and a molded product formed by the melt being cooled is withdrawn; a working fluid injecting step in which a working fluid is injected into the pipe through an injection end formed at one end of the pipe; and a finishing step in which, after the working fluid injecting step, the pipe is sealed, wherein, the pipe includes: a first pipe that is meltable by the melt and is made of aluminum material, wherein, when a high temperature melt is injected, the first pipe melts partially or entirely; and a second pipe that is disposed inside the first pipe, has a melting point higher than a melting point of the melt, has a hardness higher than a hardness of the support member, and is made of copper material, wherein an inner circumferential surface of the second pipe and the support member are pressed against each other and wherein an inner circumferential surface of the first pipe and an outer circumferential surface of the second pipe are joined. a filling step in which a predetermined support member is filled inside a pipe to prevent deformation of the pipe by a pressure of a melt being injected into a cavity (43, 44) of a mold (41, 42) that is closable; a pipe seating step in which the pipe filled with the predetermined support member is seated in the cavity (43, 44); a melt injecting step in which the melt is injected into the cavity (43, 44) to surround the pipe; a cooling and withdrawing step in which the injected melt is cooled and a molded product formed by the melt being cooled is withdrawn; a working fluid injecting step in which a working fluid is injected into the pipe through an injection end formed at one end of the pipe; and a finishing step in which, after the working fluid injecting step, the pipe is sealed, wherein, the pipe includes: a first pipe that is meltable by the melt and is made of aluminum material, wherein, when a high temperature melt is injected, the first pipe melts partially or entirely; and a second pipe that is disposed inside the first pipe, has a melting point higher than a melting point of the melt, has a hardness higher than a hardness of the support member, and is made of copper material, wherein an inner circumferential surface of the second pipe and the support member are pressed against each other and a first pipe that is meltable by the melt and is made of aluminum material, wherein, when a high temperature melt is injected, the first pipe melts partially or entirely; and a second pipe that is disposed inside the first pipe, has a melting point higher than a melting point of the melt, has a hardness higher than a hardness of the support member, and is made of copper material, wherein an inner circumferential surface of the second pipe and the support member are pressed against each other and wherein an inner circumferential surface of the first pipe and an outer circumferential surface of the second pipe are joined.