To provide a supermicro ultrasonic imaging device in which the position and attitude of an ultrasonic wave reflecting mirror can be controlled electromagnetically without use of a mechanical bearing.

An ultrasonic imaging device has a bearing-free floating rotor in order to rotate a reflecting mirror MI1, is usable for imaging from within a hollow object, and is particularly suited for the formation of an intravascular image. Floating of the rotor is effected by forming the rotor as a permanent magnet component including three magnet areas M2, M3, M4, two of the magnet areas having dipole moment opposite to the axis of the rotor, the remaining one having dipole moment transverse to the axis of the rotor, with the transverse magnet area located between the first and third magnet areas. The rotor is positioned in the direction of its axis within a housing by a positive servo feedback controller by using negative magnet levitating elements including permanent magnet stators M1, M5 on both sides of the housing, and position driving and detecting coils CO1, CO2 move the rotor and are used in detecting its position.