To solve the problem of increasing cost, due to no little labor required for disassembling work of an opening form, and of requiring careful work so as not to damage these members, when diverting the members of the form, in addition to requiring extraction of a fair number of stopping metallic materials such as nails when trying to remove the form after solidifying concrete, in the form of an opening part of a reinforced concrete wall in a present state.

This divertible form uses a construction method capable of extracting the form as it is, by sticking a tabular elastic member to two surfaces or four surfaces of the form of a header surface, so as to be removable from the solidified concrete as it is.