Provided are a mobile station and a method for providing an ultra power-saving mode in a mobile station. The method for providing an ultra power-saving mode in a mobile station includes: inactivating a communication function in a standby mode of the mobile station; extracting a DRX (discontinuous reception) cycle length coefficient K of the mobile station; determining a class-specific DRX cycle length coefficient Ni of the mobile station; replacing K with Ni; and monitoring a paging signal at a paging cycle corresponding to Ni.