A motor drive apparatus mounted with an imaging probe having a transmitting and receiving unit which carries out signal transmission and reception continuously, comprises: a scanner unit a pull-back unit and an operation unit, wherein on the side surface of the scanner unit, there are formed, at positions where facing each other, a convex portion formed for a predetermined length along the straight-ahead direction of the scanner unit, and a concave portion having an upper end surface which forms an identical surface as a lower end surface of the convex portion.
