A deflector (26, 18, 20, 38) adapted to deflect a charged particle beam, comprising: a substrate in which an opening, through which the charged particle beam should pass, is formed; a first deflection electrode and second deflection electrode which oppose each other in the opening to deflect the charged particle beam; a first insulating layer and second insulating layer which are formed between said substrate and said first deflection electrode and between said substrate and said second deflection electrode, respectively; and a first conductive layer and second conductive layer which oppose each other in the opening in a direction substantially perpendicular to a direction from the first deflection electrode to the second deflection electrode and an irradiation direction of the charged particle beam, and are made of a material having a higher conductivity than said substrate, wherein in the direction substantially perpendicular to the direction from the first deflection electrode to the second deflection electrode and the irradiation direction, a length of each of the first and second insulating layers is smaller than a length of each of the first and second deflection electrodes so as to shield the first and second insulating layers from the charged particle beam by the first and second deflection electrodes, respectively, characterized in that said deflector further comprises a third insulating layer and fourth insulating layer which are formed between said substrate and said first conductive layer and between said substrate and said second conductive layer, respectively, an interval between said first deflection electrode and said second deflection electrode is smaller than an interval between said first conductive layer and said second conductive layer, and in the direction from the first deflection electrode to the second deflection electrode, a length of each of the third and fourth insulating layers is smaller than a length of each of the first and second conductive layers so as to shield the third and fourth insulating layers from the charged particle beam by the first and second conductive layers, respectively. a substrate in which an opening, through which the charged particle beam should pass, is formed; a first deflection electrode and second deflection electrode which oppose each other in the opening to deflect the charged particle beam; a first insulating layer and second insulating layer which are formed between said substrate and said first deflection electrode and between said substrate and said second deflection electrode, respectively; and a first conductive layer and second conductive layer which oppose each other in the opening in a direction substantially perpendicular to a direction from the first deflection electrode to the second deflection electrode and an irradiation direction of the charged particle beam, and are made of a material having a higher conductivity than said substrate, wherein in the direction substantially perpendicular to the direction from the first deflection electrode to the second deflection electrode and the irradiation direction, a length of each of the first and second insulating layers is smaller than a length of each of the first and second deflection electrodes so as to shield the first and second insulating layers from the charged particle beam by the first and second deflection electrodes, respectively, characterized in that said deflector further comprises a third insulating layer and fourth insulating layer which are formed between said substrate and said first conductive layer and between said substrate and said second conductive layer, respectively, an interval between said first deflection electrode and said second deflection electrode is smaller than an interval between said first conductive layer and said second conductive layer, and in the direction from the first deflection electrode to the second deflection electrode, a length of each of the third and fourth insulating layers is smaller than a length of each of the first and second conductive layers so as to shield the third and fourth insulating layers from the charged particle beam by the first and second conductive layers, respectively.