This letter presents development of a magnetic field generator to evaluation of biological effects. The magnetic field generator has a frequency bandwidth of 85 kHz because it is intended for wireless power supply for electric vehicles. Furthermore, the generator is designed to operate for only one second, and can produce the induced magnetic field of 10 times compared to basic restrictions of the ICNIRP. By applying the magnetic field generator, it is possible to conduct a evaluation and verification of biological effect depending on electromagnetic fields for WPT systems of electric vehicles.