An electromagnetic ultrasonic transducer and an array thereof are provided. This electromagnetic ultrasonic transducer includes a support (8), an elastic board (6) disposed on the support (8), a magnetizer (7) on the elastic board (6), and a magnet field generator (1) for vibrating the magnetizer (7), wherein, the thickness of the magnetizer (7) is of the order of microns. The thickness of the elastic board (6) is also of the order of microns. This electromagnetic ultrasonic transducer is able to produce acoustic waves of high frequency, which are useful for ultrasonic therapy.