The present invention relates to a device and a method for coding a 3D video, a decoding method, according to the present invention, comprising the steps of: receiving, through a first syntax, a camera parameter for switching a depth value into a disparity value; determining whether the camera parameter which applies to a previous slice or picture applies to a current slice or picture; and if the camera parameter applies to a current slice or picture, deriving a disparity value of a current block on the basis of the camera parameter. According to the present invention, slices or pictures of a certain interval may share the same camera parameter, the transmission of overlapping information may be prevented, and coding efficiency may be improved.