In a stereoscopic video observation device 200, an optically transmissive HMD 208 presents video observed when a three-dimensional image in a virtual three-dimensional space is projected into a real space. A transmittance changing section changes the transmittance of light that passes through the optically transmissive HMD 208. A shutter control section 220 sets a lower limit value of the light transmittance that can be changed by the transmittance changing section.