Provided is a cancer treatment device which includes a first electrode and a second electrode, which are electrically connected to a signal generator and face each other with a target area therebetween, and a temperature sensor which is electrically connected to the signal generator and disposed adjacent to the target area. A cancer cell is present in the target area. The signal generator applies an AC voltage between the first electrode and the second electrode to generate an electric field between the first electrode and the second electrode. The signal generator changes an intensity of the electric field on the basis of a temperature detected from the temperature sensor. Each of the first electrode and the second electrode includes a ferroelectric material doped with manganese.