Abstract: An ultrasonic blood flow imaging apparatus of this invention includes an ultrasonic probe, a transmission system, a reception system, a B mode processing system, a CFM processing system, an FFT processing system, a video system, and a control system. The CFM processing system includes a new discriminating means. The discriminating means receives power, average blood flow velocity, and variance data output from an auto-correlation circuit. The discriminating means can discriminate Doppler shift signals (blood flow signals), noise signals, and clutter signals from each other with high precision on the basis of a relationship in combination of two or more received factors, i.e., the power, average blood flow velocity, and variance data. With such discrimination processing, only necessary blood flow signals can be extracted, and hence high-precision blood flow information can be obtained.