Here, we report the case of a patient with multiple parallel-line endotheliitis with myopic shift, which has not been previously reported. A 36-year-old man visited our clinic with blurred vision in his left eye. A slit lamp examination revealed an interesting pattern of multiple parallel lines of keratic precipitates, along with subtle corneal edema. The spherical equivalents measured in the right and left eyes were -9.25 and -11.875 diopter, respectively, with the left eye showing more myopic progression. On specular microscopy, endothelial cell loss was found in the left eye. After administration of a weak topical steroid, keratic precipitates and corneal edema resolved completely within 2 days. The myopic shift in his left eye recovered to -10.0 diopters. Multiple parallel-line endotheliitis can be easily treated with a weak topical steroid in a short period. A temporary myopic shift may occur, which in this case resolved upon disease recovery. However, corneal endothelial cell loss is inevitable; therefore, careful monitoring is needed.