WELDING METHOD, WELDING DEVICE, METAL STACKED BODY, ELECTRICAL COMPONENT, AND ELECTRICAL PRODUCT

A welding method includes: irradiating a plurality of metal foils stacked on a first surface of a metal member in a first direction with laser light to weld the metal member and the plurality of metal foils to each other, the laser light including first laser light having a wavelength of 800 [nm] or more and 1200 [nm] or less and second laser light having a wavelength of 550 [nm] or less, a second surface of a metal foil farthest from the metal member in the first direction among the plurality of metal foils, on a side opposite to the metal member, being irradiated with the laser light.