A method and an apparatus for manufacturing a high brightness electron emission device employing a thin film of a lanthanum boride compound. Sputtering particles of a low work function substance target are deposited on a second substrate on which an electron emission base member is arranged. Using a mask covering the electron emission base member region and opening the other region, deposit of thelow work function substance on the second substrate is etched and then the second substrate and a first substrate on which a phosphor is arranged are sealed with a sealing material, thereby forming avacuum container. The first and second substrates are maintained in vacuum or under reduced pressure throughout the manufacturing process.