To provide a fitting structure and a fitting method for eaves that freely adjust the right-left length of eaves and securely support the eaves.

An eaves fitting bracket 2 is fixed to an external wall 7 of a building along the external wall 7, a plurality of support arms 3 perpendicular to the eaves fitting bracket 2 are arranged at predetermined intervals along the length of the eaves fitting bracket 2, and base end parts of those support arms 3 are fixed to the eaves fitting bracket 2. A girth 4 arranged in parallel with the eaves fitting bracket 2 is fitted to tip parts of the plurality of support arms 3 to connect the tip parts of the plurality of support arms 3 by the girth 4, a plurality of support columns 5 supporting the girth 4 from below are installed at predetermined intervals along the length of the girth 4, and a roof part 6 is provided at the support arms 3 and girth 4, so that the fitting structure for eaves is provided which securely supports the eaves.