Practicability of the proposed electric-potential CT method for quantitative measurements of cracks was experimentally examined using steel plates with a two-dimensional crack. In thismethod, the observed values of electric potential distribution on the surface of a cracked body were computer-processed by an inverse numerical analysis to identify the location and size of two-dimensional cracks. As an inverse analysis scheme “the least residual method” was used in this investigation. This scheme involves boundary element analyses of electric potential for various assumed crack locations under given boundary conditions and comparison of these computed values with the observed values. The least residual criterion was used to find the most probable location of the crack. Experiments were performed for determination of location and size of two-dimensional cracks embedded in steel strips from the electric potential distribution along the side-faces. The location and size of short or long single-edge and internal cracks were determined with good accuracy, demonstrating the practicability of the proposed method.