An information recording reproducing apparatus is operable with a large-capacity recording medium and is operatively connected to a host computer. The apparatus has a cache memory for temporarily storing therein information transmitted from the host computer, and also has a write-back function and a write-through function. When recording using a write-back function designated by a recording designation flag, the maximum number of substitutions of defective sectors is automatically set to a given value for a write-back operation, and a mode display indicates that a write-back mode has been selected. The write-back operation is inhibited by a write-back inhibit flag according to the frequency of occurrence of the substitutions or the condition of a substitute area to thereby enhance the reliability of recording information.