Dynamical spin injection is attractive mean for generating and controlling the spin current without the use of the electricity. So far, the mechanism of the dynamical spin injection is attributed to the spin pumping induced by the ferromagnetic resonance (FMR). Although its quantitative evaluation is not simple because of the coexistence of the dc and ac spin pumping currents, the experimental results related to the spin pumping are mainly analyzed only by focusing on the dc spin current. Since the magnitude of the ac spin current is much larger than that of the dc spin current, the consideration of the ac spin current may be important. Apart from the spin pumping, another driving mechanism for the dynamical spin injection, we are interested in the heating effect during the resonant precession. When the temperature gradient exists across the ferromagnet/ nonmagnet interface, the spin current is generated through the thermal spin injection (spin-dependent Seebeck effect)[1,2]. In this presentation, we develop the evaluation method of the FMR heating effect for the micro- or nano-sized ferromagnet and investigate the influence of the dynamical spin injection on the magnetization dynamics.