In a recording/reproducing device for recording and reproducing an optical disk, when performing verify processing of inspecting a quality of recorded data and compare processing of inspecting whether the recorded data can be read without errors, a time is taken because the same area needs to be reproduced two times. The verify processing and the compare processing are performed at one time reproduction. To perform the verify processing and the compare processing simultaneously, a recording quality storage part is provided in the recording/reproducing device, and reproduced data is transmitted to a host controller while storing quality information at the time of reproduction by an instruction of the host controller. The host controller performs the compare processing by comparing transmitted data and data at the time of recording and inspects the recording quality by acquiring the quality information of a reproduced area from the recording/reproducing device at intervals set in advance.