We reported the anesthetic management of remimazolam, a novel ultra-short-acting benzodiazepine, for a 21-month-old female with immune-mediated necrotizing myopathy (IMNM). Remimazolam has a similar chemical structure to midazolam but possesses a unique side chain that reduces its propensity to accumulate in the body, thereby minimizing prolonged sedation or respiratory depression. Our experience supports that remimazolam could be a suitable agent for anesthetizing the patient with IMNM.