An assembly including at least one heat conductive member each constituted by an aluminum-based die-casting, and a heat pipe attached at a fixing portion thereof to the heat conductive member. The assembly is characterized in that the aluminum-based die-casting is formed of a castable aluminum alloy which includes up to 0.5% by weight of silicon; that the heat conductive member has a groove formed in a surface thereof; and that the heat pipe is accommodated at the fixing portion in the groove, and is held fixed at the fixing portion in the groove by plastically deforming at least one of opposite side walls defining the groove, toward an outer circumferential surface of the heat pipe.