Abstract: An axle driving apparatus, which contains two separately driven hydrostatic transmissions (HSTs) in a single housing, is made compact to improve the running operational efficiency of a working machine. In particular, power from a prime mover is transmitted to an input pulley so that the power is speed-changed by the two HSTs to drive left and right axles through left and right power transmitting means. The HSTs, power transmitting means and the axles are disposed substantially symmetrically laterally in the housing. The housing comprises parts coupled with each other such that joints between the parts are disposed in horizontal planes substantially parallel to the axes of rotation of the axles.