The virtual discontinuity principle of diffraction (VDPD) is a new method for the analysis of diffracted fields by three-dimensional objects that satisfies the wave equation and the boundary condition for obstacles of artitrary geometry [M. Ueda, J. Acoust. Soc. Am. 95, 2354--2362 (1994)]. In this paper, the temporal response of a diffracted field is analyzed using VDPD. To show the validity of the proposed method, the impulse response of the diffracted wave by a semi-infinite plane is calculated and compared with both the exact solution and the experimental result. The experiment is carefully performed by using an ideal discharging point source and a 1/4-in. wideband transducer (B&K, type 4135). The proposed method showed good agreement with the exact solution and the experimental result. It also reduces the computational load by an order of magnitude because it does not require a double integral as required in the conventional technique.