Presently, the number of asteroids is known to be more than 740,000. Asteroids are thought to be the remnants of planetesimals formed in the early solar system, and allow us to study the formation and evolution of the solar system, as well as the origin of life. We performed two kinds of asteroid surveys with the Japanese infrared satellite AKARI. The first one is the mid-infrared survey to construct the size and albedo catalog of 5120 asteroids. Thanks to the 16-month continuous survey, the Asteroid catalog using AKARI, or AcuA, provides a 100% complete data set of all asteroids larger than 20 km, corresponding to more than 98% of the total mass of all asteroids in the main belt region. The second one is the near-infrared spectroscopic survey to search for water on asteroids. In order to explore the existence of water in the present solar system, it is important to investigate the presence of hydrated minerals and/or water ice on asteroids. These water-related materials show absorption features in the 3-micron band, which can only be observed by space-borne telescope without disturbance of atmospheric absorption. We carried out a spectroscopic survey of 66 asteroids with AKARI in the 2.5-5 micron wavelength range. From these observations, it is found that most C-type asteroids have clear absorption features related to hydrated minerals. In this talk, I will present the detail of these AKARI asteroid surveys.