As an application of ultrasonic motors becomes popular, an ultrasound transmission line (UTL) is required to be efficient. Actually, we are developing a puncture type ultrasonic microscope [1] using a miniature ultrasonic motor for scanning. We have to supply a flexural wave through a thin UTL to rotate the motor. In general, when an UTL touches neighboring covers, the propagating wave drastically attenuates. Hence, we are examining the UTL which is fixed to the cover by retainers located every a half wavelength for forming a cascade-connection resonator in it. We reported the resonance property evaluated through simulations as a standing wave for a longitudinal wave [2]. In this study, we confirm the energy distributed in the UTL to clarify the resonance characteristics for a flexural wave that is suitable for driving our motor.