Under the limited frequency band of the ultrasonic probe, at least one of the transmitting frequency band or the receiving frequency band becomes narrower if being divided into the transmitting wave and the frequency band from the receiving wave of the contrast agent. An ultrasonic imaging apparatus of the invention, detecting a signal peculiar to a contrast agent emitted when liquid formed in a fine particle vaporizes due to ultrasonic waves and imaging space distribution thereof. A narrow band is used for transmission, a broad band is used for a received signal, and in a state of high spaceresolution of the received signal, a transmission signal and the received signal are discriminated.