The portable device for caching RF-ID tag data and method thereof

A portable device capable of reading the RF-ID tags are provided. The portable device includes a memory unit and a tag information for storing the tag information detected by the RF-ID RF-ID reader portion for detecting the tag information stored in the tag, RF-ID reader portion is for RF-ID tag in the enabled state If the reading instruction input and supplies the read out the tag information stored in the memory unit, when the RF-ID tag reading command is input while tag information is not valid, for controlling RF-ID reader portion for reading the RF-ID tag, and a controller. The control unit may determine the validity of the tag information based on the time and location. Accordingly, it is possible to reduce unnecessary tags reading operation, it is possible to prevent the power consumption, it is possible to shorten the verification time tag information. RF-ID tag, the tag information, a memory unit, the effective time, the effective distance