To provide an energy filter whose vacuum inside exposed surface area is small and by which positioning accuracy of magnetic pole pieces is enhanced and whose cost can be reduced and by which the edge magnetic field distribution is reduced and whose manufacturing and assembling accuracy can be enhanced, and a transmission type electron microscope having this.

Magnetic pole pieces 2a, 3a (2b, 3b) to constitute magnetic poles are integrally molded in a projecting shape in yoke members 1a and 1b. An exciting coil arranged in the atmosphere and vacuum packing 8a, 8b, 9a and 9b, are arranged on the magnetic pole pieces. Grooves 81 and 82 to pass an electron beam are arranged in a yoke between the magnetic poles. Passing holes of the electron beam are arranged in intermediate rings 35 and 36 to press down the vacuum packing around the magnetic poles.