Bending test of rectangular plate in the condition of all edges built in is one of the most troublesome one. In this fifth report, in order to experiment on the bending of orthogonally stiffened plate in such condition, adequate bending moments are given along four edges, in consequence, equivalent values. of all edges built in are obtained. Comparing these data with the value derived from the orthotropic plate theory illustrated in the first report, it shows fairly agreement between them, and it is, concluded that the orthogonally stiffened plate in such condition can be also expressed satisfactory by the orthotropic plate theory as shown in the preceding reports. Some notes about the approximate method to derive the deflection of orthotropic rectangular plate with all edges built in are also given, as the regorous method is rather complicated.