Magnetic toner for developing electrostatic image

A magnetic toner for developing an electrostatic image, comprising a binder resin, a magnetic material and a compound represented by the following formula (I):

• ##STR8## wherein R.sup.1 and R.sup.2 are each a member selected from the group consisting of a hydrogen atom, a sulfonic acid group, a carboxylic acid group, a carboxylate group, a hydroxyl group and a halogen atom, and may be the same or different;
• n.sub.1 and n.sub.2 are each an integer of 1 to 4;
• X.sup.1 and X.sup.2 are each a member selected from the group consisting of a hydrogen atom and a halogen atom;
• m.sub.1 and m.sub.2 are each an integer of 1 to 3;
• and A.sup..sym. is a member selected from the group consisting of a hydrogen ion, an alkali metal ion and an ammonium ion;
• said magnetic toner having a saturation magnetization of from 20 Am.sup.2 /kg to 50 Am.sup.2 /kg and a coercive force of from 40 oersted to 200 oersted, wherein the magnetic material is contained in an amount satisfying the following expression:
• MT=-(10/3).times.d+(70.+-.15)
• wherein MT represents a content in % by weight of the magnetic material, and d represents a weight average particle diameter (.mu.m) of the magnetic toner, provided that d is not more than 9 .mu.m.