A method for designating a dual region according to one embodiment of the present invention comprises the steps of: enabling a terminal which is in communication with a first network to calculate a channel state threshold value corresponding to data; comparing the channel state value of the first network and the channel state value of the second network, acquired using a pilot signal of a second network, with the channel state threshold value; calculating a network evaluation score of the first network; comparing the network evaluation score of the first network with a network evaluation threshold value for designating a dual region, if the channel state value of the first network and the channel state value of the second network are larger than the channel state threshold value; and determining whether to designate a dual region in accordance with the result of the comparison using the network evaluation threshold value. The method of the present invention can reduce service cutoff or delay time during inter-radio access.