In recent years, from the viewpoint of saving energy, it is requested that the toner can be fused at lower energy. And the speed of machine system is increasing year by year. So, high durability toner is requested as well. However, it is very difficult to satisfy high durability and excellent fusing ability at the same time. Conventionally low temperature fusing is realized by reducing the molecular weight of the binder resin. However the binder resins having narrow molecular weight distribution, low melt viscosity, low glass transition temperature, low durability. In order to solve the problem, we have synthesized several branched polyester, by controlling the kinds of branching agent and amounts of branching agent, various kinds of branched polyester are prepared. And the effects of branching agents and amounts for the physical properties of toner were investigated.