The present invention aims to provide an anode active material for a sodium ion battery with favorable rate characteristic. The object is attained by providing an anode active material for a sodium ion battery comprising an active substance having an MNb3O8 phase belonging to an orthorhombic crystal (M is at least one kind of H, Li, Na and K), and a carbon material contacting with the active substance, wherein the active substance and the carbon material are composited.