An inexpensive bonding method is provided to bond materials constituted of an aluminum-based metal to each other at a low temperature and a low pressure while inhibiting deformation, without requiring the use of a flux and minimizing the influence on the base materials and the periphery. Also provided are various bonded parts obtained by the bonding method. An insert material comprising Zn as an element that undergoes a eutectic reaction with Al is interposed between two materials constituted of an aluminum-based metal. The two materials are heated, while being pressed against each other, to a temperature at which the eutectic reaction takes place, thereby generating, at the bonding interface between the two materials, a melt due to the eutectic reaction with some of the Al contained in the base materials and discharging the Al oxide films from the bonding interface together with the melt. Thus, the two materials are bonded.