Composite manufacturing method, composite manufacturing apparatus, and composite

Provided is a composite manufacturing method capable of suppressing bonding defects even when the intensity of irradiated laser light is not uniform at a bonding surface. The composite manufacturing method includes a surface treatment step and a bonding step. In the surface treatment step, the first surface of the first member is subjected to surface treatment processing for changing the absorptivity of the laser light. In the bonding step, in a state where the second surface of the second member is brought into contact with the surface-treated first surface, laser light is irradiated from the surface of the second member on the opposite side from the second surface toward the first surface without scanning, and the first surface and the second surface are bonded. The first surface has: a first portion in which the intensity of laser light irradiated in the bonding step is a first intensity; and a second portion in which the intensity of the laser beam irradiated in the bonding step is a second intensity that