To provide an acceleration and deceleration method for turning acceleration and deceleration time at the time of elevating and lowering a moving member in a vertical direction to a minimum time.

In this acceleration and deceleration method of the moving member elevated and lowered in the vertical direction such as the main axis head 2 and saddle table, etc., of a machine tool, so as to finely adjust the acceleration and deceleration speed of the vertical axis servo motor SM of an NC controller 13 by a correction set value 12 from the setting device 11 of a time constant for which weight information from a weight sensor LC for detecting the vertical weight of the moving member 2 is a correction amount, the time constant which is the correction set value is made large and acceleration is slowly performed at the time of elevating acceleration against gravity, the time constant is made small and deceleration is quickly performed at the time of deceleration, the time constant is made small and the acceleration is quickly performed at the time of lowering the moving member 2 in the vertical direction and the time constant is made large and the deceleration is slowly performed at the time of the deceleration.