Transient scattering by a metal cylinder covered with inhomogeneous lossy material is analyzed for application of radar systems to nondestructive testing of reinforced concrete structures. First, inhomogeneous lossy material that is a model of corrosion by rust is approximated by a cylindrical multilayered medium, and analytic solution of a scattered field in frequency domain is derived. Next, time domain scattering response is calculated from the frequency domain data by using the inverse Fourier transform. Numerical results of pulse responses indicate that corrosion rate of the concrete can be evaluated by checking the waveform distortion of the pulse responses.