PROBLEM TO BE SOLVED: To provide an ultrasonic diagnostic device which can reduce a burden on an operator and a subject at the time of data collection in contrast radiography.SOLUTION: A collection part 152 collects signal strength of a harmonic component in an analysis area set within an ultrasonic scan region of a subject to which a contrast medium is administered along a time series. An analysis part 153 analyzes the time series data of the signal strength and calculates a change pattern indicating the secular change of the signal strength in the analysis area characteristically. A determination part 154 obtains reliability of the analysis result using the time series data at the present time point on the basis of the change pattern calculated from the time series data collected by the time point before the present time point, determines whether or not it is the state where the collection of the signal strength can be completed or the position of the analysis area in the subject is changed on the basis of the obtained reliability, and notifies the operator of the determination result.
