A surgical apron sheet to cover the face to prevent eye inflammation and the like caused by, inter alia, scattering oral bacteria, while also facilitating treatment of the oral cavity. The surgical apron sheet has a structure that resists slipping when covering the face during treatment of the oral cavity and is easy to manufacture at low cost. The surgical apron sheet of apron shape includes a face covering portion to cover the face of a patient during treatment and provided with a mouth-like opening. The opening is provided at a lower end with an engaging portion cut as a long hole of substantially semi-elliptic shape to engage a submental region or lower jaw line of the patient being treated.