To build high-reliability software in software development, software review is essential. Typically, software review requires documents from multiple phases such as requirements specification, design document and source code to reveal the inconsistencies among them and to ensure the traceability of deliverables. However, most previous studies on software review (reading) techniques focus on finding defects in a single document in their experiments. In this paper, we propose a multi-document review evaluation system, DRESREM 2. This system records reviewers' eye movements and mouse/keyboard operations for analysis. We conducted eye gaze analysis of reviewers in design document review with multiple documents (including requirements specification, design document, etc.) to confirm the usefulness of the system. For the performance analysis, we recorded defect detection ratio, detection time per defect, and fixation ratio of eye movements on each document. As a result, reviewers who concentrated their eye movements on requirements specification found more defects in the design document. We believe this result is good evidence to encourage developers to read high-level documents when reviewing low-level documents.