procedure is followed that corresponds reversely to the block diagram in fig1 in order to achieve the foregoing the selective signal a 39 of the transform at the energy detection means 3 is also transmitted through the transmission terminal the decoding device receives this selective signal a 39 for decoding the transmitted data according to fig3 the transmitted signal encoded by the encoding device as depicted in fig1 is variable length decoded at variable length decoding vld means 10 the signal decoded at the vld means 10 is transformed into an original bit stream through inverse run amplifier transforming means 20 the signal which has been transformed into a bit stream at the inverse run amplifier converting means 20 is inverse quantized at inverse quantization means 30 the inverse quantized signal is input to inverse transforming means 40 having a plurality of inverse transforms itf1 tf2 itfn corresponding to the transforms in transforming means 8 in fig1 the signal input in parallel to respective inverse transforms of the inverse transforming means 40 is inversely transformed and is outputted to a multiplexer 50 the selective signal a 39 generated from the energy detection means 3 of fig1 is input to the multiplexer 50 through a transmission line the multiplexer 50 outputs only the inverse transform signal of the inverse transforms itf1 itfn identified by the selective signal a 39 out of the inversely transformed signals output from the inverse transforming means 40 accordingly a decoded signal is obtained as illustrated in the foregoing the present invention provides for encoding and decoding through adaptive selection the invention employs at least two different kinds of transforms selectively encodes.