To provide a new usage (that is, a binder resin for excellent toner) of a cellulose, using the cellulose which is a carbon neutral material, and to provide toner which can be kneaded at a low kneading temperature, a developer which can lower an image fixing temperature, and a binder resin for toner capable of forming the toner and the developer, by containing a cellulose derivative having a low softening temperature.

A binder resin for toner contains a cellulose derivative containing at least one group in which the hydrogen atom of a hydroxyl group contained in a cellulose is substituted by (A) a group containing a structure represented by general formula (1) and at least one group in which the hydrogen atom of the hydroxyl group contained in the cellulose is substituted by (B) an acyl group: -CO-RB (RB is a hydrocarbon group). (In the general formula (1), n represents 2 or 3 and RA represents a hydrocarbon group).