Abstract: An ultrasonic diagnosing apparatus displaying blood flow data. A Doppler shift signal is detected from a reception signal obtained by an ultrasonic transducer by transmitting/receiving an ultrasonic wave to/from an object. Doppler data obtained from this detection signal is written in a memory. Monochromatic ultrasonic image data and the Doppler data are used to perform color processing of the ultrasonic image data in accordance with the Doppler data. The apparatus includes a mixing/processing section and a switching control section. The mixing/processing section includes a reversing section for reversing display colors associated with moving directions by performing complement processing of the Doppler data read out from the memory, and a selector section for selecting one of the reversed and the non-reversed Doppler data. The mixing/processing section mixes the selected Doppler data with the ultrasonic image data.