A drive assembly for a track-type vehicle which makes the effective ground contact length within the tumbler distance as large as possible. The drive assembly has a single track roller unit disposed closest to the idler and closest to the sprocket respectively, each for supporting the track roller rotatably at the distal end portion of an arm attached at its proximal end portion rockably to the track frame and for bearing a vehicle body load at the distal end portion of the arm through elastic members, and a double track roller unit interposed between the single track roller units and including a first arm attached at its proximal end portion to the track frame and a second arm attached at its central portion to the distal end portion of the first arm, for supporting the paired lower rollers at the two end portions of the second arm.