Provided is a method of manufacturing a composite metal material which includes a first metal member made of first metal and a second metal member made of second metal having a smaller linear expansion coefficient than first metal. The method includes in the following order: a metal member preparation step of preparing the first metal member made of first metal and a plurality of divided members made of second metal; an assembling step of assembling the respective metal members into an assembled body; and a bonding step of, by applying a first temperature and a first pressure which enable the respective metal materials to be bonded to each other to the assembled body, bonding the plurality of divided members to each other thus forming the second metal member and also of bonding the first metal member and the second metal member to each other.