To provide a control actuator and a vibration control method capable of performing the optimum vibration test by easily performing multi-point excitation in a multi-degree of freedom vibration system or capable of easily constituting an apparatus using the multi-point excitation.

The control actuator 10 exciting each part of a plurality of vibration objects while performing distributed control for self-oscillation at a prescribed natural frequency includes an oscillation element 16 in which a positive feedback control element 12 with a phase delay of 90 and a negative feedback element 14 with a phase delay of 90 are coupled in parallel. The control actuator 10 further includes an excitation instruction means 18 applying a prescribed periodic signal for self-oscillation, a saturation element 20 regulating the maximum value of a control output at a constant value or less, and a vibration control element 22 adding apparent attenuation.