A drill for sinus membrane lift includes a contact surface for coming in face contact with sinus membrane, the contact surface having a curved periphery, and a bone-maintaining area connected to the contact surface for storing and discharging drilled bone fragments. The bone-maintaining area includes a first inside wall and a second inside wall connected to the first inside wall, the first inside wall oriented in a drilling direction, and the second inside wall opposite the first inside wall. The first inside wall has a drilling surface and is formed higher than the second inside wall so that the drilling surface is exposed in the drilling direction. The front end of the head comes into face contact with the sinus membrane at a wide area to prevent the sinus membrane from being torn or damaged even if the head completely penetrates the maxilla and contacts the sinus membrane.
