The present invention provides a one-component development type developing apparatus including a rotatable electrostatic
latent image holding member 1 on the surface of which an electrostatic
latent image is formed, and using a toner 4 for rendering the electrostatic
latent image visible, wherein when the shape factor SF-1 of a toner fine particle is expressed by: SF-1=(M2 / A)×(π / 4)×100 where A is the
projected area of the fine particle and M is the
absolute maximum length of the fine particle, then the shape factor SF-1 of the toner 4 is at least 100 and at most 140, and the developing apparatus includes: a toner holding member 3 that is formed from a
silicone rubber elastic material and that is for holding the toner 4 and transporting it to the electrostatic latent image holding member 1; a toner layer regulating member 9 for forming the toner on the toner holding member 3 into a
thin layer; and a toner supply member 5 that is formed from a
silicone rubber foam and that rotates, in a position opposed to the toner holding member 3, in a direction opposite to that of the toner holding member 3, and an AC
electric field is formed between the toner holding member 3 and the toner supply member 5.