Beam detector, multi-charged particle beam irradiation device, and adjustment method for beam detector

Provided are a beam detector, a multi-charged particle beam irradiation device, and a method for adjusting the beam detector, wherein holes having two-stage apertures are aligned with each other with high accuracy. A beam detector according to one embodiment of the present invention is provided with: a first aperture substrate in which a first through hole is formed; a second aperture substrate having formed therein a second through hole through which the one beam to be detected, which has passed through the first through hole, can pass; and a sensor that detects a beam current of the detection target beam that has passed through the second through hole. The second aperture substrate contains a conductive material, and a plurality of third through-holes through which light can pass are formed around the second through-hole. 提供一种将两级孔径的孔高精度地对位的束检测器、多带电粒子束照射装置及束检测器的调整方法。本发明的一个方式的束检测器具备：第1孔径基板，形成有第1穿过孔；第2孔径基板，形成有能够供穿过上述第1穿过孔后的1条检测对象束穿过的第2穿过孔；以及传感器，检测穿过上述第2穿过孔后的上述检测对象束的束电流；上述第2孔径基板包含导电性的材料，在上述第2穿过孔的周围形成有能够供光穿过的多个第