Crack is a damage usually happened in structural members but dangerous for safety of structure if it is not early detected. However, cracks are often difficult to identify by visual inspection as they occurred at the unfeasible locations. Therefore, cracks could be indirectly detected from measured total dynamical characteristics of structures such as natural frequencies, mode shapes and frequency or time history response. In order to identify location and size of a crack in a structure the problem of analysis of the crack’s effect on the dynamic properties is of great importance. It could give also useful tool for crack localization and size evaluation. On the other hand, beams are frequently used as structural member in the practice of structural engineering. So, crack detection for beam-like structures gets to be an important problem. Crack detection problem of beam with uniform cross section is thoroughly studied, but vibration of cracked beam with varying cross section presents a difficult problem. It is because vibration of such the structure is described by differential equations with varying coefficients that are nowadays not generally solved. The beam with piecewise uniform beam, acknowledged as stepped beam is the simplest model of beam with varying cross section. Although, vibration analysis and crack detection for stepped beam have been studied in some publications, developing more efficient methods for solving the problems of various types of stepped beams is really demanded