Abstract: A machine tool position correcting method and apparatus applied to a machine tool including a spindle head provided on a column and a ram which is movable horizontally on the spindle head and has a main shaft to which a tool is mountable. In the arrangement, a quantity of horizontal movement of the ram is detected, a quantity of vertical correction of the ram is calculated on the basis of the detected quantity of horizontal movement of the ram, and the spindle head is moved vertically, while keeping a horizontal position thereof, on the basis of the calculated quantity of vertical correction of the ram. Since a vertical deviation of the ram has a correction to its quantity of horizontal movement, the vertical deviation, or quantity of vertical correction, of the ram is obtained by detecting its quantity of horizontal movement.