The encoding rate controlling apparatus (9) is provided with a controlling device (9a, 9b) for performing a control for the encoding rate by changing a quantization scale code for quantizing the dynamic image information, and for conversing an average value of the encoding rate through all of the dynamic image information to an average value corresponding to a predetermined average value. The controlling device establishes on a time axis a plurality of change timings, each of which is a timing when the quantization scale code is changed, calculates the average value of the encoding rate corresponding to each of the established change timings, and performs the control for the encoding rate on the basis of the calculated average value. An information encoding apparatus (S) has the encoding rate controlling apparatus, a quantizing device (3) for quantizing the dynamic image information by using the changed quantization scale code, and an encoding device (5) for variable-length-encoding the quantized dynamic image information.