To provide an image bit stream conversion apparatus for carrying out proper coding control compatible with a scene momentarily having a high coding difficulty for each scene and carrying out the optimum coding processing with a small code amount.

A database management circuit 108 acquires a correction value of a parameter for controlling the coding processing from a scene information database 104 on the basis of information associated with a genre of a video image being an object of the coding processing obtained by a genre/keyword searching circuit 103 and scene characteristic information representing the characteristic of each scene separated by a scene separation circuit 107 on the basis of coding information obtained by a coding information calculation circuit 105 in the case of decoding an image bit stream of the object video image, and a coding control parameter setting circuit 113 sets the parameter on the acquired correction value and carries out re-coding.