To provide a charged-particle beam aligner which prevents an organic dirt foreign matter, which causes a reduction in the pattern transfer characteristics of the aligner in parallel with a reduction of the exposure operation of the aligner, from being solidified in the aligner.

When a pattern 16 of a molding diaphragm 7 is transferred on resist on a wafer 12 with an accelerating electron beam, an organic dirt foreign matter is adhered on a blanker 2, a premolding stop 4, a molding deflector 6, the molding diaphragm 7, a subdeflector 9, a focal point correction lens 10, a main deflector 11 and an objective 13, which are members which are arranged on the radiation path of the accelerating electron beam, with organic gas which is generated from the resist by irradiation with the accelerating electron beam, but even though the organic dirt foreing matter is adhered on the members, the organic dirt foreing matter is decomposedly vaporized and is removed from the members by electron-hole pairs, which are formed of a photocatalyst film on these members, by irradiation with the accelerating electron beam, whereby it becomes possible to efficiently perform an operation to prevent the dirt foreign matter, which causes a reduction in the pattern transfer characteristics of a charged-particle beam aligner in parallel with a reduction in the exposure operation of the aligner, from being solidified in the aligner, by the simple constitution of the aligner.