A focused ion beam apparatus includes an ion source that emits an ion beam, an extraction electrode that extracts ions from a tip end of an emitter of the ion source, and a first lens electrode that configures a condenser lens by a potential difference with the extraction electrode, the condenser lens focusing the ions extracted by the extraction electrode, in which a strong lens action is generated between the extraction electrode and the first lens electrode so as to focus all ions extracted from the ion source to pass through a hole of the condenser lens including the first lens electrode.