We report a case of heat stroke in which detection of brain injury was improved by high b-value diffusion-weighted imaging (DWI). High b-value DWI revealed moderate to marked hyperintensity at/around bilateral dentate nuclei and part of thalami. Apparent diffusion coefficient maps revealed apparent diffusion coefficient decrease of the dentate lesions. Routine DWI showed only mild hyperintensity of part of dentate lesions. High b-value DWI could be valuable for improved detection of heat stroke-induced brain injury.