A wood planing machine includes a base adapted to permit a workpiece to be moved thereon in a front-to-rear direction, a plurality guide posts fixed on the base, a mounting seat sleeved movably on the guide posts, a motor disposed on the mounting seat, and a cutting unit disposed on the mounting seat. The cutting unit includes a rough-plane cutter, a fine-plane cutter disposed behind the rough-plane cutter, a first transmission unit interconnecting the motor and the rough-plane cutter to allow the rough-plane cutter to be driven by the motor, and a second transmission unit interconnecting the rough-plane cutter and the fine-plane cutter to allow rotation of the rough-plane cutter to be transferred to the fine-plane cutter.