Two solutions of SH transient problem for the elastic half-space and SH transient reflection problem from a micro plane crack lying in the elastic half-space are analytically connected, finally we calculate numerically SH transient response for semi-infinite elastic wave guide subjected to the lateral impact load. The Cagniard method gives the exact solution of an anti-plane deformation problem which SH impulsive load acts on the free surface of an elastic half-space. After having applied the WienerHopf technique for the transient reflection response from a micro plane crack and the method of images for the transient reflection response from the free boundaries of the elastic wave guide, consequently we are obtaining the precise and rational transient responses for an elastic wave guide with several micro cracks.