Abstract: A metal member and a resin member, or two resin members are welded or bonded to each other at welding or bonding surfaces thereof which are heated by irradiation of a laser beam, thereby providing an assembly wherein the two members are fluid-tightly bonded at the bonding surfaces. The laser beam is transmitted through a laser transmitting resin, and a laser absorbing material which is in contact with the laser transmitting resin is irradiated with the laser beam, so that the laser absorbing material is heated, whereby the laser transmitting resin and the laser absorbing resin are melted owing to the heat. By moving the spot of the laser beam, portions of the resin members to be heated and melted displace, and the resin materials are melted and then solidify.

Abstract: A metal member and a resin member, or two resin members are welded or bonded to each other at welding or bonding surfaces thereof which are heated by irradiation of a laser beam, thereby providing an assembly wherein the two members are fluid-tightly bonded at the bonding surfaces. The laser beam is transmitted through a laser transmitting resin, and a laser absorbing material which is in contact with the laser transmitting resin is irradiated with the laser beam, so that the laser absorbing material is heated, whereby the laser transmitting resin and the laser absorbing resin are melted owing to the heat. By moving the spot of the laser beam, portions of the resin members to be heated and melted displace, and the resin materials are melted and then solidify. The casing 202 includes an upper part 216 formed of the laser absorbing resin and a lower part 218 formed of the laser transmitting resin.