1. An ultrasonic diagnostic apparatus characterized by comprising: an ultrasonic probe for transmitting/receiving an ultrasonic wave to/from an object while the object is pressed; a phasing and adding unit for generating RF signal frame data of a cross-sectional site of the object on the basis of a reflection echo signal measured by the ultrasonic probe; an ultrasonic image generating unit for generating an ultrasonic image of the cross-sectional site of the object on the basis of the RF signal frame data; a measurement target setting unit for setting a measurement target to the RF signal frame data or the ultrasonic image; a measurement target position tracing unit for tracing a positional variation of the set measurement target; a displacement image generating unit for generating a graph representing transition of a press state applied to the measurement target on the basis of the positional variation of the measurement target; and a display unit for displaying the generated graph.