1. A 3-D image display unit for displaying a 3-D image configured by a plurality of images, including: an input part for inputting control information required to display said 3-D image, wherein said control information includes information that denotes the 3-D effect intensity of said 3-D image; a calculation part for calculating an accumulative intensity value that increases together with a display time of said 3-D image according to said 3-D effect intensity; and a display control part for making a predetermined display operation when said accumulative intensity is over a first threshold value.