An apparatus and method for imaging a shear modulus within a body is disclosed. A method for imaging a shear modulus in accordance with the present invention includes generating an elastic wave inside an object to be measured detecting the elastic wave ongoing inside the object to be measured calculating a shear modulus of the inside of the object to be measured, based on a value obtained by differentiating the detected elastic wave one time and imaging the inside of the object to be measured, based on the calculated shear modulus.