The present invention relates to a precoding matrix information transmission method and a user device, and provides a method for transmitting precoding matrix information by a particular user device among user devices that receive a signal transmitted from one base station. The method comprises the steps of: determining, from a predetermined codebook, a first precoding matrix which is a precoding matrix for the particular user device during signal reception, and determining one or more second precoding matrices for the other user devices which are to be multiplexed in a predetermined resource region with the particular user device, wherein the one or more second precoding matrices are determined within a codebook subset of the predetermined codebook linked with the first precoding matrix; and transmitting, to the base station, first precoding matrix information indicating the first precoding matrix and second precoding matrix information indicating the one or more second precoding matrices.