Ultrasonic diagnostic apparatus

An ultrasonic diagnostic apparatus including a probe which transmits a burst wave of ultrasonic pulses into a target in a body and receives reflected echo signals, a transmission unit which drives the probe, a receiver which delays the echo signals from the probe by delay times substantially equal to the delay times in the transmission unit, 2D image processing unit which performs predetermined processing on the output signals from the receiver in order to indicate a tomographic image, a Doppler-mode processing unit which performs predetermined processing on the output signals from the receiver in order to indicate the frequency spectrum of the received signals, a display unit which displays each processed result from the a 2D image processing unit and the Doppler-mode processing unit, a sample volume setting device which designates an observation region (sample volume) such as observation length (spatial length of the sample volume) and observation location (sample volume depth) to obtain a Doppler shift frequency, and a control unit which controls the transmission unit and the Doppler processing unit so that a width of a range gate is smaller than the width of an observation region designated by the sample volume setting device.