Provided is a highly efficient, slim heat transfer apparatus, including a main body connected to an end of a condensing zone through a liquid coolant reservoir. An extension of the main body is connected to the other end of the condensing zone. The main body has a coolant reservoir that stores liquid coolant supplied from the condensing zone, a vaporization zone in which the liquid coolant supplied from the coolant reservoir is vaporized, and a channel region connecting the coolant reservoir to the vaporization zone. The channel region acts as a channel for supplying the liquid coolant from the coolant reservoir to the vaporization zone.