An electron-emitting element is provided which lessens the necessary voltage to be applied to a grid electrode and accurately and precisely controls electron emission from a cathode electrode. This is achieved by a field emission type electron-emitting element wherein an electric field existing between the grid electrode (3) and an anode electrode emanates from an electron passage opening in the grid electrode (3) to the cathode electrode (2) side and interacts with an electric field existing between the cathode electrode (2) and the grid electrode (3) such that a combined electric field is formed, and an electron-emission controlling element is provided which varies the intensity of the combined electric field by varying the potential of at least one of the cathode electrode (2), the anode electrode, and the grid electrode (3).