PROBLEM TO BE SOLVED: To provide an induction and initial phase control system and method for a spin wave capable of controlling an initial phase of an induced spin wave obtained by irradiating a sample with a pump beam.SOLUTION: An induction and initial phase control system for a spin wave comprises: a light source 3; a polarization azimuth angle rotation device 4 that can rotate a polarization azimuth angle &phgr; of a pump beam emitted from the light source 3; and a sample 2 arranged on an optical path where the pump beam passes in the polarization azimuth angle rotation device 4, and that can induce a spin wave. The pump beam is emitted toward the sample 2 to induce the spin wave in the sample 2. By changing the polarization azimuth angle &phgr; of the pump beam by the polarization azimuth angle rotation device 4 on the basis of a predetermined formula, an initial phase C of the induced spin wave can be controlled.
