An information recording apparatus (SS1) is provided with: a quantize device (72, 72B) for quantizing record information by 8×n bits; a divide device (72, 72D) for dividing the quantized record information quantized at one quantization timing, into (i) high order bit quantized record information (66), which is a portion at high order 8×m bits of the quantized record information including a predetermined portion of the record information, which must be reproduced at a time of reproducing the record information, and (ii) low order bit quantized record information (67), which is another portion of the quantized record information; a multiplexed record information generation device (72, 72E) for constituting (i) a high order bit quantized record information block (UB) including a plurality of high order bit quantized record informations corresponding to consecutive quantization timings and (ii) a low order bit quantized record information block (DB) including a plurality of low order bit quantized record informations corresponding to the consecutive quantization timings, and for multiplexing the constituted high order bit quantized record information block and the constituted low order bit quantized record information block adjacent to each other to thereby generate multiplexed record information (Sr).