Device of the reduction gear or differential type for a turbine engine of an aircraft. A central sun gear and a row of planet gears, each of the planet gears are rotationally guided by at least one bearing extending around a tubular support. The tubular support includes an inner cavity for the reception of oil and through-orifices for the passage of oil of the tubular support to the at least one bearing. A member for circulating the oil is mounted in the cavity and includes at least one oil duct intended to be connected to an oil supply. The oil is intended to flow from the at least one duct into the inner cavity to form an oil film in contact with said tubular support, and to flow through the orifices.