A method and apparatus for displaying three-dimensional CT (Computed Tomography) data as a combination of three sectional images defined by an X-section, a Y-section and a Z-section orthogonalizing each other and the recoding medium saving a program for realizing the method are disclosed together. According to the method, when a cursor on one of the three sectional images is moved, another sectional image sequentially changed corresponding to a movement of the cursor.