PURPOSE:To propagate an electric signal and power without contact, by providing coils in respective materials moving relatively and by coupling coils as a transformer in the time when respective materials face to each other. CONSTITUTION:A disc-shaped magnetic substance 6b having an L-form section and a magnetic substance 6c having a T-form section are fixed to a cylindrical nonmagnetic substance 6a, and coils 8 and 9 are wound around magnetic substances 6b and 6c to constitute a moving material. Meanwhile, a magnetic substance 7a having a recess-form section and magnetic substances 7d and 7e having an L-form section are fixed to plates 7b and 7c of nonmagnetic substances, and coils 10-13 are arranged on magnetic substances 7a, 7d, and 7e to constitute a fixed material. The moving material moves along the fixed material while rotating in the direction of an arrow III to propagate signals and power by coupling of coils. This device is applied for an ultrasonic beam scanner.