To provide a decoration fish bolt mounting structure which contributes to improve mounting efficiency by curtailing field work having been conventionally required when a decoration fish bolt is mounted on an eaves gutter or the like of a wooden building, facilitates mounting/removing work of the bolt after completion of the mounting work, simplifies maintenance and repair of the bolt, and enables reuse of the same.

According to the decoration fish bolt mounting structure, a first horizontal slot 27b extending in the horizontal direction is formed in a rear surface of the decoration fish bolt 27, and bolt substrates 36, 37 are fixed to the decoration fish bolt so as to cover the rear surface except for the first horizontal slot. Then, a fascia substrate 35 which almost conforms in shape to the rear surface of the bolt and has a first linear projection 35a capable of fitting into the first horizontal slot, is fixed to a mounting surface for an eaves gutter or the like. While the first linear projection formed on the fascia substrate is fitted into the first horizontal slot formed in the rear surface of the decoration fish bolt, the substrates are detachably fastened to the fascia substrates by means of fasteners 32, 34 such as screws.