PURPOSE: To realize the variable length code table control system, which can compose a variable length code table of a little ROM or RAM even when the number of bits in the longest code among variable length codes is increased, concerning the variable length code control system for coding input data into the variable length codes.

CONSTITUTION: At a variable length coding circuit composed of a variable length code table 10 to output the variable length codes with an input data value as an address, data exchange circuit 20 to exchange the variable length codes outputted from the variable length code table 10 and buffer memory 30 to write the outputs of the data exchange circuit 20 and to output them corresponding to the output speed of a transmission line, the table in a compressed data form is written in the variable length code table 10, the contents of the variable length code table 10 are read out with the input data as the addresses in the case of variable length coding, and an extending means 40 is provided to return the relevant compressed data to the original variable length codes.