A vertical saw machine includes a column with upper and lower supports carrying a motor to drive a saw blade. A table is disposed between the upper and lower supports for supporting a workpiece. The saw blade intersects the table with an included angle. The column is turnable between normal and inclined positions to vary the included angle. A frame post is mounted under the table to be positioned on the ground surface. A key slot and a key member are disposed respectively in and on the frame post and the column, and confine an arcuate guiding route to retainingly guide the column to move between the two positions.