A defect repair apparatus for an EUV mask has an ion beam column that scans and irradiates the EUV mask with a focused hydrogen ion beam such that no region of the EUV mask receives an amount of beam irradiation exceeding 4×1016 ions/cm2. The ion beam column comprises a gas field ion source having an emitter with a pointed tip end that emits hydrogen ions that form the hydrogen ion beam, and an ion optical system that focuses and scans the hydrogen ion beam onto the EUV mask. A detector detects secondary charged particles generated from the EUV mask when irradiated with the hydrogen ion beam, and an image forming section forms and displays an observation image of the EUV mask on the basis of an output signal from the detector so that a defect in the EUV mask and the progress of the defect repair can be observed.