A heat pipe has a flat container; a wick structure housed inside the flat container; and a working fluid sealed inside the flat container, wherein in at least one cross section of the flat container, the wick structure contacts both of the pair of flat inner surfaces of the flat container, and both side faces of the wick structure do not contact any of the inner surfaces of the flat container, wherein the wick structure has a first wick part and a second wick part, respectively disposed in the lengthwise direction of the flat container, the second wick part being directly or indirectly connected to the first wick part and having a maximum width that is wider than a maximum width of the first wick part, and wherein the second wick part is disposed in the heat receiving portion of the heat pipe.