Abstract: A planing machine includes a carriage locking mechanism disposed above a cutter carriage, which in turn, is connected movably to upstanding posts of a machine base that is disposed below the cutter carriage. The locking mechanism includes a pair of post bracing members, each of which extends at one side of a respective pair of the posts, and has two post embracing units that embrace the respective pair of the posts. The post bracing members are mounted on the carriage. A right regulator plate is disposed above the carriage, and has a first end portion connected pivotally to the right post bracing member, and a second end portion formed with a wheel accommodating slot. A left regulator plate has a first end portion fixed to the left post bracing member, and a second end portion overlapping the second end portion of the right regulator plate.