The Curie temperature of in inhomogeneous and homogeneous (single phase) states is controlled by heat treatment and hydrogen absorption. The magnetization change at around room temperature of the inhomogeneous specimens composed of -Fe, LaFeSi, and phases becomes sluggish after hydrogen absorption, because in the specimens has a distribution accompanied by some inhomogeneity of the hydrogen content. As a result, the magnitude of the isothermal magnetic entropy change due to the itinerant-electron metamagnetic transition of these specimens is decreased by hydrogen absorption. On the other hand, the magnitude of after hydrogen absorption into the single-phase specimen is almost the same as that before hydrogen absorption. Consequently, the compositional homogenization in is necessary to obtain large magnetocaloric effects around room temperature.