Abstract: A two-stage planetary gear transmission having a first-stage planetary gear transmission and a second-stage planetary gear transmission is disclosed, wherein the carrier of the second-stage planetary gear transmission comprises first and second carrier parts integrally connected with each other. A hollow pinion shaft formed thereon with the sun gear of the second stage is rotationally supported on the first carrier part via a deep-channel ball bearing in a cantilevered condition. A carrier of the first stage for supporting planetary gears of the first stage is integrally formed on the end of the hollow pinion shaft of the second stage. A lubricant layer of about 15 .mu.m to about 20 .mu.m in width is formed between an inner race member of a planetary bearing and a planetary shaft for each of the planetary gears of the second stage.