Effect of elastic modulus of matrix on ferromagnetic motion of NiMnGa particles was investigated for NiMnGa particles embedded silicone matrix composites with or without containing polystyrene form particles (PFPs), which are regarded as pores. NiMnGa single crystal was fabricated by a floating zone method and a cube-shape particle was fabricated with the surface orientation parallel to ,  and  directions at the parent phase state. The elastic modulus of matrix polymer was controlled by changing the number of PFPs. It was found that the elastic modulus of silicone was decreased with increasing the volume fraction of PFPs. The magnetic-field-induced martensite variant reorientation (MVR) was evaluated by the magnetization curves obtained using a vibration sample magnetometer, and the magnetic field required for the start of martensite variant reorientation was reduced by increasing the number of PFPs. The control of elastic modulus of matrix polymer is important and a dominant factor for the magnetic motion of NiMnGa/polymer composites.