Composite body manufacturing method, composite body manufacturing device, and composite body

A composite body manufacturing device, the device manufacturing a composite body in which a first member and a second member are bonded, the first member being made of metal, the second member being made of a resin transmissive to a laser light, the device comprising:

• a surface treatment part performing a surface treatment processing of a first surface of the first member to change an absorptance for the laser light,
• a bonding part bonding the first surface having undergone the surface treatment processing and a second surface of the second member by irradiating the laser light, without scanning, toward the first surface from a surface of the second member at a side opposite to the second surface in a state in which the first surface is caused to contact the second surface,
• the first surface including
• a first portion in which an intensity of the laser light irradiated by the bonding part is a first intensity, and
• a second portion in which the intensity of the laser light irradiated by the bonding part is a second intensity, the second intensity being less than the first intensity,
• the surface treatment part performing the surface treatment processing so that a second absorptance becomes greater than a first absorptance,
• the second absorptance being an absorptance of the second portion for the laser light,
• the first absorptance being an absorptance of the first portion for the laser light.

A composite body, comprising:

• a first member including a first surface, the first member being made of metal;
• and
• a second member including a second surface, the second member being made of resin,
• the first surface and the second surface being bonded,
• the first surface including a first region and a second region,
• a surface roughness of at least a portion of the second region being greater than a surface roughness of at least a portion of the first region.