The present invention relates to wireless communication, and more particularly, to a method for a machine-to-machine (hereinafter abbreviated M2M) communication applied M2M device to update information in a wireless communication system and terminal thereof. In decoding superframe header subpacket information in an M2M (machine to machine) device in idle mode in a wireless communication system, the present invention includes comparing a paging cycle with a 1st cycle and if the paging cycle is equal to or greater than the 1st cycle, decoding the superframe header subpacket information, wherein the 1st cycle is determined using a following formula: I=C×2n, where the I indicates the 1st cycle, the C is a change cycle of a secondary superframe header, and the n is a bit size of a change count of the secondary superframe header.