To provide an automatic binder and a binding method for binding in a hexagon without cutting a hoop or generating a scratch on a binding material such as a steel round rod material.

This relates to an automatic binder and a binding method which automatically selects a regular hexagonal or an irregular hexagonal bound form best suited for the number of materials to be bound and binds the materials in the selected bound form, or binds the materials to be bound in a bound form in a regular hexagon or an irregular hexagon selected by a worker to suit the number of materials to be bound using a list, etc., prepared in advance.