A table containing correspondence between “n” and “m” is set in a control circuit of a servo control system so that the current command data in the m-th (m=1, 2, 3 . . . ) current command register is assigned to the n-th (n=1, 2, 3 . . . ) servo amplifier. When data is specified in this table to satisfy “n=m”, the current command data in the n-th current command register is passed to the n-th servo amplifier. When “m=1” is set for “n=1” and “m=1” is set for “n=2” in this table, the current command data stored in the first current command register is passed to the first and second servo amplifiers.