A device and method for inputting keys in a portable terminal, where a key used for performing functions of the portable terminal can be easily input. The device includes a key input unit including keys that have at least two regions on each key wherein data are arranged on each key to correspond to each region. The device also includes a controller unit for displaying the data on one of at least two regions of a key. For example, the region corresponds to a key input when the key provided to the key input unit is inputted and thereafter, displays only data arranged on a region in a corresponding region input mode of displaying only data arranged on one of at least two regions of a key when the key provided to the key input unit is inputted or displays data set to a key group including the inputted key.