Pulsed eddy current (PEC) technique is used for detection of surface and near surface flaws in electrically conducting materials. To extend the capability of the PEC technique to detect deep sub-surface flaws in thick non-magnetic materials, it is essential to enhance the sensitivity of the PEC instrument and PEC probe. In this paper, a high-sensitive PEC instrument that driver higher excitation currents is designed and developed. Further, finite element model is used to compare the detection performance of three different PEC probe configurations and to select the optimal probe configuration for detection of deep sub-surface flaws. Using the developed PEC instrument and optimized probe, it is possible to detect flaws located at 6.0 mm below the surface in an 8.0 mm thick stainless steel (SS) plate.