nozzle-type electron beam irradiation device comprising a vacuum nozzle insertable into an opening (m) of an irradiation object, the opening (m) being formed on the irradiation object, the nozzle-type electron beam irradiation device comprising a vacuum chamber and an electron beam generator disposed in the vacuum chamber, the vacuum nozzle being connected to the vacuum chamber so as to guide an electron beam from the electron beam generator and emit the electron beam to outside, the nozzle-type electron beam irradiation device comprising: a magnet that surrounds the vacuum nozzle from the outside and focuses the electron beam guided into the vacuum nozzle; an inserting/removing mechanism that inserts and removes the vacuum nozzle into and from the opening (m) of the irradiation object; a connecting member connecting the vacuum chamber and the vacuum nozzle, the connecting member containing the magnet inside the connecting member, the vacuum nozzle being disposed with a base end embedded in the connecting member; characterized in that the magnet is a neodymium magnet, and in that the nozzle-type electron beam irradiation device further comprises a cooling mechanism that cools the vacuum nozzle, the cooling mechanism cooling the neodymium magnet so as to prevent irreversible demagnetization while cooling the vacuum nozzle, the cooling mechanism comprising a coolant passage that allows passage of a coolant, the coolant passage being disposed between the vacuum nozzle and the neodymium magnet so as to surround the vacuum nozzle in the connecting member. the nozzle-type electron beam irradiation device comprising a vacuum chamber and an electron beam generator disposed in the vacuum chamber, the vacuum nozzle being connected to the vacuum chamber so as to guide an electron beam from the electron beam generator and emit the electron beam to outside, the nozzle-type electron beam irradiation device comprising: a magnet that surrounds the vacuum nozzle from the outside and focuses the electron beam guided into the vacuum nozzle; an inserting/removing mechanism that inserts and removes the vacuum nozzle into and from the opening (m) of the irradiation object; a connecting member connecting the vacuum chamber and the vacuum nozzle, the connecting member containing the magnet inside the connecting member, the vacuum nozzle being disposed with a base end embedded in the connecting member; characterized in that the magnet is a neodymium magnet, and in that the nozzle-type electron beam irradiation device further comprises a cooling mechanism that cools the vacuum nozzle, the cooling mechanism cooling the neodymium magnet so as to prevent irreversible demagnetization while cooling the vacuum nozzle, the cooling mechanism comprising a coolant passage that allows passage of a coolant, the coolant passage being disposed between the vacuum nozzle and the neodymium magnet so as to surround the vacuum nozzle in the connecting member. a magnet that surrounds the vacuum nozzle from the outside and focuses the electron beam guided into the vacuum nozzle; an inserting/removing mechanism that inserts and removes the vacuum nozzle into and from the opening (m) of the irradiation object; a connecting member connecting the vacuum chamber and the vacuum nozzle, the connecting member containing the magnet inside the connecting member, the vacuum nozzle being disposed with a base end embedded in the connecting member; characterized in that the magnet is a neodymium magnet, and in that the nozzle-type electron beam irradiation device further comprises a cooling mechanism that cools the vacuum nozzle, the cooling mechanism cooling the neodymium magnet so as to prevent irreversible demagnetization while cooling the vacuum nozzle, the cooling mechanism comprising a coolant passage that allows passage of a coolant, the coolant passage being disposed between the vacuum nozzle and the neodymium magnet so as to surround the vacuum nozzle in the connecting member.