Abstract: A magnetizing apparatus capable of magnetizing a magnetic roller having a length up to 30 cm is provided. The magnetizing apparatus is comprised of at least two split members, each of which is provided with magnetic heads employed for applying magnetic fields to a magnetic roller. The end face of each magnetic head is shaped in agreement with the profile of the magnetic roller so that there would be no air gap formed between the magnetic head and the magnetic roller when they come into contact with each other. The split members are separated first and then combined to accommodate the magnetic roller within the magnetizing apparatus. After magnetization, a magnetic force is induced between the magnetic head and the magnetic roller such that an external force stronger than the magnetic force is used to pull the split members apart to fetch out the magnetic roller.