1 . A heat sink comprising: a plurality of heat pipes to be thermally connected to a heating element comprising an electronic component; and a heat dissipation section, comprising at least one fin, thermally connected to the plurality of heat pipes, wherein in the plurality of heat pipes, at least evaporation sections to be thermally connected to the heating element have flattened portions whose cross sectional shape in a direction orthogonal to a heat transfer direction of the plurality of heat pipes is flattened, and a surface in between the flattened portions of the heat pipe is arranged facing the heating element, the heat pipe has a longitudinal direction being vertical and a short direction being horizontal, wherein the flattened portions are located in the longitudinal vertical direction, only a part of a surface in the longitudinal direction of the flattened portion is embedded in a first surface of a heat reception plate, the heating element is thermally connected to a second surface corresponding to a surface on an opposite side of the first surface of the heat reception plate, the evaporation sections of the plurality of heat pipes are arranged apart from each other, the flattened portions of the plurality of heat pipes are arranged apart from each other and separated by the heat reception plate on the first surface of the heat reception plate, a cover member that is separate from the heat reception plate, the cover member covering the heat reception plate and the heat pipe, each of the heat pipes has a first wick structure corresponding to fine grooves formed on an inner surface of a container, a second wick structure and a third wick structure, the third wick structure is formed in a layered manner along the surfaces of the flattened portion in the short direction, the third wick structure is formed to be continuous to the second wick structure in a cross section in the direction orthogonal to the heat transfer direction of the heat pipe, the second wick structure has a wall thickness larger than that of the third wick structure and the second wick structure protrudes relative to the third wick structure disposed in a layered manner, two protrusion portions of the second wick structure are arranged facing each other, a material of the second wick structure is the same as a material of the third wick structure, the two protrusion portions of the second wick structure are spaced apart without contact, with flat surfaces of the second wick structures facing each other running parallel to each other and along the longitudinal direction, in an area where the second wick structure, which has a wall thickness larger than that of the third wick structure is present, the heat pipe has both portions that are not embedded in the heat reception plate and portions which are embedded in the heat reception plate such that the recirculation property of the liquid working fluid is increased, and heat equalized in the heat reception plate is transferred to the heat pipes at the area where the heat pipes are embedded in the heat reception plate.
2 . The heat sink according to claim 1 , wherein the evaporation section of the heat pipe is located in one end portion of the heat pipe, and a condensation section of the heat pipe to be thermally connected to the heat dissipation section is located in another end portion of the heat pipe.
3 . The heat sink according to claim 1 , wherein the evaporation sections of the plurality of heat pipes are arranged in parallel along an extending direction of the heating element.