are constant in the radial direction. The abundance ratios against Fe in the central region (0–10 kpc) are 0.66$\pm^{0.07}_{0.06}$ solar, 1.35$\pm^{0.12}_{0.10}$ solar, 1.32$\pm^{0.06}_{0.07}$ solar, 1.32$\pm^{0.11}_{0.10}$ solar for O, Ne, Mg, Si, respectively. The O/Fe ratio is similar to that of NGC 1404 (Matsushita et al. 2007a) and NGC 720 (Tawara et al. 2006) measured by the XIS, and also with the RGS results for NGC 4636 (Xu et al. 2002) and NGC 5044 (Tamura et al. 2003). This indicates that a common metal production process has taken place in elliptical galaxies. However, the Mg/Fe ratio of NGC 4636 is higher than that of NGC 1399 in the outer region. This difference might be caused by different populations of SN II progenitor stars between the two galaxies, but problems with the plasma emission model cannot be ruled out (Matsushita et al. 2003). It is noticeable that the radial profile of the O abundance of NGC 4636 exhibits a steeper gradient than other elliptical galaxies, NGC 1399 , NGC 5044, and NGC 507. This indicates that NGC 4636 keeps metals more tightly concentrated. NGC 4636 is rather isolated and has never been identified as a galaxy group; the other galaxies are classified 