A composite member in which WC-based cemented carbide members are bonded to each other via a bonding layer formed by solid phase diffusion bonding of a bonding member made of a Ti foil. The bonding layer is constituted by first layers adjacent to the WC-based cemented carbide members and made of a TiC phase and a metal W phase in which an average area ratio of the TiC phase is 40 to 60%. The bonding layer also includes second layers adjacent to the first layers and made of a TiCo phase and a metal Ti phase in which an average area ratio of the TiCo phase is 50 to 95%, and a residual Ti layer.