A method for producing a welded resin material contains steps of: superimposing a resin member having transmissibility to laser light and a resin member having absorptivity to laser light to form a contact part where the resin members are in contact with each other; forming a closed space that is adjacent to the contact part and faces one end of the contact part; and radiating the laser light from the resin member having transmissibility while pressing the resin members to each other through the contact part, so as to heat the contact part to melt a resin at the contact part, housing a resin excluded from the contact part through melting in the closed space, solidifying the resin melted at the contact part to weld the resin members.