In relation to the criterion for ignition of a combustible gas flowing at high speed over a wedge at a high surface temperature, the method of large activation energy asymptotics was employed to investigate the characteristics of ignition and to derive an explicit expression for an ignition criterion including the effects of general Prandtl (Pr) number and wedge angle. Based on this criterion, the regions of ignition and lack of ignition were identified over the surface of the wedge for various wedge angles.