An information recording/reproducing apparatus wherein the CPU stores data transferred through an interface in a temporary storage area and later records the data in a recording medium by using a recording/reproducing means. The temporary storage area is divided into first and a second regions by a temporary storage region disposition device. A discriminator determines whether the process-requested region is an information managing region or a data region from the process requests made by the host computer and the temporary storage region managing information. Based on the result of this discrimination, the temporary storage region manager allocates the first region if the data is for information managing or the second region if the data is intended for data storage.