PURPOSE: To efficiently set target input position data with high precision by performing positioning control while repeatedly correcting a transfer function shown by a specific expression.

CONSTITUTION: An input 1 is calculated from a desired response O by using a transfer function H1 found from a known input and a response and instructed as target input position data to a numerically controlled incompletely round work machining device. At this time, a transfer function H2 is calculated by using a response Oi in a frequency range by the equation unless the obtained response 1 has an error converged within a desired permissible value. A new input 2 is calculated as the target input position data from the desired response by using this transfer function H2. This operation is repeated until the error is converged and repeated while the transfer function is corrected until a specific control result is obtained to enable the numerically controlled incompletely round work machining with high precision. In the equation H(jw) is the frequency transfer function, I(jw) is the target input position data (frequency range), and O(jw) is actual movement data (frequency range) on a machining tool.