A foam filling member having simplified structure is provided that may be produced with improved working efficiency and at low cost. Additionally, the invention enables a reduction in a quantity of foaming material of the foaming base used for filling an interior space of a structure. The foam filling member has an annular wall formed on a supporting plate and an annular foaming portion of the foaming base supported on an outer supporting portion located at the outside of the annular wall on the supporting plate. A plurality of openings are formed in the annular wall and also lugs are formed that project into an inner closed portion at the inside of the annular wall through the respective openings.