This is the first report showing the clinical course of a patient with bilateral IgG4-related dacryoadenitis, which spontaneously regressed after excision of the left lacrimal gland. A 65-year-old female had been aware of bilateral eyelid swelling without pain for 5 years. Magnetic resonance imaging revealed enlargement of bilateral lacrimal gland. Laboratory tests showed high IgG4 concentrations, measuring 394 mg/dl. The biopsied specimen of the left lacrimal gland revealed marked lymphoplasmacytic infiltration with mild fibrosis. Marked IgG and IgG4-positive plasma cells surrounded the lymphoid follicles. Although the patient did not wish to undergo any treatments, lacrimal gland lesions showed gradual remission. This case highlights the potential of spontaneous improvement in IgG4-related dacryoadenitis, indicating that careful observation may be one of the therapeutic options for such patients.