A welding method and welding apparatus for resin members is provided in which dimensional accuracy of two resin members after welding can be secured and reduction in joining strength due to excessive laser irradiation can be prevented. In a method of superimposing a resin having a laser-transmitting property and a resin having laser absorptiveness and irradiating the resin members with a laser beam from the side of the laser-transmitting resin member to deposit the resin members on each other, irradiation with the laser beam is ended in accordance with reduction in the approaching speed of the two resin members during the irradiation with the laser beam.