A 60-year-old woman underwent 80 mg BCG (Tokyo strain) intravesical instillation therapy for high-grade pTa bladder cancer. She presented with fever (>48 hours), knee joint pain, and conjunctival hyperemia after receiving four infusions. She was administered 10 mg/day of prednisolone (as per 0.2 mg/kg body weight), an NSAID (loxoprofen sodium hydrate, 180 mg/day), and antituberculosis drugs (isoniazid (INH), 300 mg/day; rifampicin (REP), 450 mg/day; and ethambutol (EB), 750 mg/day) because she was diagnosed with BCG-induced Reiter syndrome. She was administered steroid pulse therapy (methylprednisolone, 1000 mg/day) for three days because high white blood cell (WBC) and C-reactive protein (CRP) levels and fever persisted. After the third day of administration, fever, joint pain, and inflammation improved quickly. Subsequently, the dose of prednisolone was gradually reduced to a maintenance dose of 30 mg (as per 0.6 mg/kg body weight), and the symptoms did not recur.