PURPOSE: To make a magnetic toner suitable for use in a copying machine with a developing sleeve rotating at a high speed by adding a dehydrogenated compound of a specified ferrocene polymer as a magnetic substance.

CONSTITUTION: This magnetic toner contains at least a binding resin and a magnetic substance and this magnetic substance is an org. magnetic substance obtd. by dehydrogenating the principal chain of a ferrocene polymer represented by the formula with an oxidizing agent. In the formula, R is alkyl, aryl, alkenyl, aralkyl or aralkenyl and (n) is the degree of polymn. The ferrocene polymer is a ferrocene/benzaldehyde condensation polymer, a ferrocene/cinnamic aldehyde condensation polymer, a ferrocene/crotonaldehyde condensation polymer, a ferrocene/n-nonylaldehyde condensation polymer, etc.