PURPOSE: To suppress excessive acceleration of a tilling apparatus and to perform smooth control of lifting motion.

CONSTITUTION: This lift controlling apparatus is provided with a positional deviation detection means A to get the deviation of the present level of a rotary tiller from an arbitrarily set target level and with a controlling level setting means C to receive the positional deviation from the positional deviation detection means, convert the deviation value to a membership value by a preset membership function, determine the control target based on the membership value and the membership function and use the control target as a value for adjusting the opening of a control valve V of a hydraulic actuator 7 to vertically move the rotary tiller to a side to decrease the positional deviation.