Survey of the Galactic center with IRSF/SIRIUS - near-infrared extinction law and bulge structure

Since 2001, we have observed the central region of our Galaxy with the near-infrared (J, H, and Ks) camera SIRIUS and the 1.4 m telescope IRSF. Here I present the results about the infrared extinction law and the structure of the Galactic Bulge with bulge red clump stars. From the observation of the red clump stars, we have determined directly the ratios of extinction to color-excess (A_Ks/E(H-Ks) and A_Ks/E(J-Ks), which are clearly less than the ratios determined by previous color-differences methods. We also find a smaller structure (|l| <~ 4°) inside the Galactic bar although its exact nature is as yet uncertain.