To facilitate manufacturing and processing of a filler metal and improve strength by restraining segregation at a jointing portion.

According to this laser welding method, base materials 10A, 10B of an aluminum plated steel plate are irradiated with a laser beam 12, and a filler wire 16 of an aluminum alloy is supplied to a molten pool 14 being thus generated, so that an alloyed part 18 of the filler wire 16 and the base materials 10A, 10B is formed. If the filler wire 16 is supplied to the molten pool 14 generated by radiating the laser beam 12 to the base materials 10A, 10B, the filler wire 16 and the base materials 10A, 10B are evenly mixed. Therefore, since segregation and the like can be restrained, the strength of a joint portion can be improved.