An electron beam generating apparatus for an electron beam source having surface conduction electron emitting devices formed on a substrate; includes a measuring unit for measuring a device current flowing through each of the surface conduction electron emitting devices, an a device current storage unit for storing data measured by the measuring unit. In addition comparing unit compares latest data measured by the measuring unit with the data stored in the device current storage unit, a correction value storage unit stores a correction value for correcting a driving signal to be applied to each surface conduction electron emitting device, and an adjusting unit adjusts the correction value stored in the correction value storage unit.