Disclosed are a statistical multiplex system, a statistical multiplex controller and a method of statistical multiplex, which can assign bit rates to program data and auxiliary data efficiently, and also improve image quality. A statistical multiplex system is provided with: a plurality of image encoders for encoding a plurality of program data; an information encoder for encoding the auxiliary data; a multiplexing apparatus for multiplexing output thereof, and a statistical multiplex controller for controlling each of the image encoders and the information encoder. The statistical multiplex controller is made to set the bit rate to be assigned to the information encoder first, and to assign the remaining bit rates to each of the image encoders.