Disclosed herein is a capacitor for a magnetron. The capacitor has dielectric members, which have a converging angle of less than 180° defined between lines extending from both sides of each dielectric member formed between corresponding ends of inner and outer electrodes of the dielectric member. The capacitor is reduced in size while having enhanced capacitance, thereby reducing a manufacturing time. The capacitor also has central conductors having enlarged portions larger than the inner electrode, thereby further enhancing the capacitance.