A cutting depth setting device is provided for a saw machine which includes a base portion having a positioning block protruding therefrom, a drive arm pivotally engaged with the base portion about a pivot axle, a protruding block projecting from the drive arm and located above the positioning block, a threaded hole vertically defined through the protruding block, a circular saw blade rotatably mounted on the drive arm to pivot therewith for cutting a workpiece, a working platform mounted beneath the saw blade for holding the workpiece, the cutting depth setting device including an adjusting bolt threadedly extending through the threaded hole of the protruding block to be displaced vertically relative to the protruding block, a head fixedly mounted on an upperside of the adjusting bolt for rotating the adjusting bolt, a pointer pivotally engaged on an underside of the adjusting bolt to move vertically therewith, a first panel movably mounted on the drive arm and having a flat surface which is located adjacent to the pointer and has a plurality of graduations formed thereon for aligning with the pointer, and a second panel movably mounted on the drive arm and enclosed on the first panel, and a plurality of numerals formed on the second panel for respectively aligning with the plurality of graduations.