A charged particle beam device comprising: - a charged particle source configured to emit a charged particle beam; - an acceleration electric power source connected to the charged particle source and configured to accelerate the charged particle beam emitted by the charged particle source; - a second objective lens configured to focus the charged particle beam onto a sample; and - a second detector (110; 210; 610; 820) configured to receive an electromagnetic wave that the sample emits upon incidence of the charged particle beam thereon, and configured to carry out a detection of the electromagnetic wave thus received, - the second objective lens being positioned on the opposite side of the sample from where the charged particle beam is incident on the sample, - the second detector (110; 210; 610; 820) being positioned on the same side of the sample as where the charged particle beam is incident on the sample, the second objective lens including: - a central magnetic pole having a central axis coinciding with an ideal optical axis of the charged particle beam; - an upper magnetic pole; - a side-surface magnetic pole in a cylindrical shape; and - a lower magnetic pole, - the central magnetic pole having an upper portion that is so shaped as to have a diameter which is smaller at a position further above and having a lower portion in the shape of a column, the upper portion being close to the sample, - the upper magnetic pole having an opening at a center thereof and being in the shape of a disk that is tapered to the center and that is thinner at a position closer to the center of gravity of the central magnetic pole. - a charged particle source configured to emit a charged particle beam; - an acceleration electric power source connected to the charged particle source and configured to accelerate the charged particle beam emitted by the charged particle source; - a second objective lens configured to focus the charged particle beam onto a sample; and - a second detector (110; 210; 610; 820) configured to receive an electromagnetic wave that the sample emits upon incidence of the charged particle beam thereon, and configured to carry out a detection of the electromagnetic wave thus received, - the second objective lens being positioned on the opposite side of the sample from where the charged particle beam is incident on the sample, - the second detector (110; 210; 610; 820) being positioned on the same side of the sample as where the charged particle beam is incident on the sample, the second objective lens including: - a central magnetic pole having a central axis coinciding with an ideal optical axis of the charged particle beam; - an upper magnetic pole; - a side-surface magnetic pole in a cylindrical shape; and - a lower magnetic pole, - the central magnetic pole having an upper portion that is so shaped as to have a diameter which is smaller at a position further above and having a lower portion in the shape of a column, the upper portion being close to the sample, - the upper magnetic pole having an opening at a center thereof and being in the shape of a disk that is tapered to the center and that is thinner at a position closer to the center of gravity of the central magnetic pole.