We report the discovery of a high-temperature source above the soft X-ray loop of the impulsive limb flare on 1992 January 13 with the Yohkoh Soft X-ray Telescope (SXT). The hot source coincides in position with the loop-top impulsive hard X-ray source and continues to sit above the soft X-ray flare loop throughout the flare. The single high-temperature source in the initial phase evolves to the two high-temperature (15-20 MK) ridge structures in the peak and decay phases, and the compact hard X-ray source appears to be located in between the high-temperature ridges. We assume that the loop-top hard X-ray source is of thermal origin (superhot source). The loop-top hard X-ray source has an effective temperature of 100-150 MK and a total emission measure of ~10-4 of the hot source. The geometrical relationship between the superhot and the hot sources indicates that (1) the hot source is heated by the slow shocks associated with magnetic reconnection and that (2) the superhot source is heated with the fast bow shock owing to the collision of the supersonic downward outflow with the reconnected flux tube. The small emission measure of the superhot source indicates a narrow outflow jet in between the slow shocks. These observations suggest that there is no essential difference between the compact-loop (impulsive) and long-duration event (LDE) flares. The time coincidence of the loop-top hard X-ray source with the footpoint sources indicates that nonthermal electron acceleration is causally related to the formation of the fast shock rather than the slow shocks.