An ultrasonic diagnostic apparatus includes: a positional displacement calculating section for calculating the magnitudes of positional displacements at multiple measuring points within a body tissue a thickness variation calculating section for calculating thicknesses or thickness variations, each measured between two arbitrary points within the tissue set with respect to the measuring points, based on the magnitudes of positional displacements and a maximum/minimum value calculating section for finding the maximum and minimum thicknesses or thickness variations during a maximum value finding period and a minimum value finding period. At least one of the greatest thickness difference, strain and elastic property is calculated based on a difference between the maximum and minimum thicknesses or thickness variations.
