Provided are an ultrasonic diagnostic apparatus that constructs and displays a 3-dimensional elastic image showing the hardness or softness of a biological tissue in an object to be examined, and a method of displaying an ultrasonic image. The ultrasonic diagnostic apparatus is provided with an RF signal frame data storing unit (20) that stores a predetermined range of RF signal frame data based on the reflected echo signals received by the reception unit (4), an RF signal frame data selecting unit (21) that selects the RF signal frame data in the predetermined range stored in the RF signal frame data storing unit (20), an elasticity information calculating unit (23) that calculates strain or elastic modulus from the RF signal frame data in the predetermined range, and a 3-dimensional elastic image constructing unit (28) that constructs a 3-dimensional elastic image on the basis of the calculated strain or elasticity modulus.
