To provide an external wall material mounting structure improving efficiency in external wall material mounting work, allowing the removal of only a specific external wall material in case it is damaged or the like, and hardly causing a sense of incongruity in appearance even if replaced with a new external wall material.

Hook parts 22 of two adjacent ones of a plurality of external wall material support members 2 mounted in parallel at constant spaces to an external wall backing part 1 are caught getting into recesses 9 of side face parts of external wall materials 3 while being elastically deformed in contact with fitting lead-in parts 15 formed at the side face parts 6, or the hook parts 22 slip out to fit the external wall materials to the external wall material support members at the side face parts or to release the fitting.