To provide a method for controlling electron flow, which eliminates power loss in a field emission type electron source and enables power-saving and miniaturization of an apparatus using the field emission type electron source.

In the field emission type electron source which emits electrons by being applied with an electric field, a conductive material 12 is placed around an emitter 11 which emits an electron flow to a target 3, and the electron flow to be fed to the target is controlled by applying a voltage negative to the emitter 11 to the conductive material 12.