Automation of vehicles can be expected to improve safety, comfort and efficiency, and is being developed in various countries. Introduction of automated driving can be ranked from 0 to 5 (0: no automation, 1: driver assistance, 2: partial automation, 3: conditional automation, 4: high automation, 5: full automation). Currently, feasible automation levels are considered to be levels 2 or 3, and human manual take-over from the automated system is needed when the automated system exceeds these levels. In this situation, time required for take-over is an important issue. This study focuses on describing driving simulator experimental results of time required for take-over. The experimental scenario is that the automated system finds an object ahead during automated driving on the highway, and issues a take-over request to the driver. The subject driver can be in the following driver situations: hands-on or hands-off the steering, and strong or weak distractions. In these situations, we examine two kinds of take-over time, which are 7 and 5 seconds. The results show all subjects complete take-over actions properly even if the required time is 5 seconds. In this paper, details of these results are described.