We propose 100 ksec observation of the Sgr C cloud in the Galactic center region. The cloud emits strong 6.4-keV line, and is a candidate of X-ray reflection nebula; the molecular cloud which emits fluorescence and scattered X-rays irradiated by an external X-ray source. The past activity of Sgr~A$^*$, the Galactic nucleus, may be the origin of 6.4-keV line. We will study 6.4-keV line and verify the X-ray reflection scenario. The second objective is to study the distribution of high ionized and neutral iron lines in the GC region. Chandra observation indicates that H-like iron line is very strong in this region. With the higher energy resolution of XIS, we can confirm the Chandra results. High energy diffuse emission above 10 keV is also a important target by HXD.