A mechanism for attaching an ultrasonic head of an ultrasonic microscope to a vibration shaft of a vibrator is disclosed. A first connector half to which an R.F. cable is connected is fixedly arranged to the vibration shaft and a second connector half having the ultrasonic head coupled therewith is detachably attached to the first connector half, so that an exchange of the ultrasonic head can be performed in an easy and swift manner without affecting the position and characteristics of the R.F. cable.