A composite printed wiring board that allows for reflow heating for mounting electronic components using solder includes a first printed wiring board, an intermediate member, a second printed wiring board, and a bonding layer. The intermediate member is stacked on the first printed wiring board. The intermediate member has a cavity. The second printed wiring board is stacked on a surface on the opposite side to a surface opposed to the first printed wiring board in the intermediate member. The bonding layer is arranged at a bonding section between the first printed wiring board and the intermediate member and at a bonding section between the second printed wiring board and the intermediate member. The bonding layer contains high melting point metal and low melting point metal. The melting point of the bonding layer is higher than the melting point of the low melting point metal.