PURPOSE: To reflect the changing state on the inference result and to accurately perform the control by inferring a target speed by using the preceding target value as an input variable and outputting this target speed together with the target value inferred by a target value inference means.

CONSTITUTION: This device consists of the target value inference means which infers the target value based on the input variable and a target speed inference means which infers the target speed based on the present target value. That is, the target value as the inference result of the target value inference means is inputted to the target speed inference means together with the preceding target value, and the target speed inference means executes the fuzzy inference to infer the target speed based on the preceding target value and the present target value. This target speed is outputted together with the target value inferred by the target value inference means, and this inference result includes the degree of urgency based on the changing state. Thus, the changing state of the inference result of the target value due to fuzzy inference is taken into consideration and is outputted as the target speed.