According to the present invention, an oriented magnetic steel sheet is provided with linearly extending reflux-magnetic-domain regions periodically formed, in a direction in the range 60-120 degree inside a steel plate surface with respect to the rolling direction, at an interval in the rolling direction of s (mm), said oriented magnetic steel sheet having an actually measured plate thickness of t (mm). The depth h ([mu]m) and width w ([mu]m) of the reflux-magnetic-domain regions are configured so as to be in a range which satisfies each of the following relationships: h >= 74.9t + 39.1 (0.26 >= t); h >= 897t - 174.7 (t > 0.26); (w*h)/(s*1000) <= -12.6t + 7.9 (t > 0.22); and (w*h)/(s*1000) <= -40.6t + 14.1 (t <= 0.22). As a result, an oriented magnetic steel sheet exhibiting low iron loss within a broad plate thickness range can be achieved.