A stereoscopic video observation device comprising: an optically transmissive HMD configured to present video observed when a three-dimensional image in a virtual three-dimensional space is projected into a real space, and configured to present a stereoscopic video by a three-dimensional monitor of a frame sequential system; a transmittance changing section configured to change transmittance of external light passing through the optically transmissive HMD; a shutter control section configured to set a lower limit value of the light transmittance that can be changed by the transmittance changing section; and a motion detecting section configured to obtain a change in position coordinates of the stereoscopic video observation device, wherein the shutter control section changes the lower limit value of the light transmittance that can be changed by the transmittance changing section on a basis of a rate of change in the position coordinates, the rate of change in the position coordinates being obtained by the motion detecting section, wherein the transmittance changing section changing the transmittance of the light passing through the optically transmissive HMD is a liquid crystal shutter for observing the three-dimensional monitor of the frame sequential system, and the shutter control section changes the light transmittance by controlling a period during which the transmittance is set at 0% by turning on the shutter of the transmittance changing section, a period during which the transmittance is set higher than 0% by turning off the shutter, and an angle of polarization of a liquid crystal when the shutter is off. an optically transmissive HMD configured to present video observed when a three-dimensional image in a virtual three-dimensional space is projected into a real space, and configured to present a stereoscopic video by a three-dimensional monitor of a frame sequential system; a transmittance changing section configured to change transmittance of external light passing through the optically transmissive HMD; a shutter control section configured to set a lower limit value of the light transmittance that can be changed by the transmittance changing section; and a motion detecting section configured to obtain a change in position coordinates of the stereoscopic video observation device, wherein the shutter control section changes the lower limit value of the light transmittance that can be changed by the transmittance changing section on a basis of a rate of change in the position coordinates, the rate of change in the position coordinates being obtained by the motion detecting section, wherein the transmittance changing section changing the transmittance of the light passing through the optically transmissive HMD is a liquid crystal shutter for observing the three-dimensional monitor of the frame sequential system, and the shutter control section changes the light transmittance by controlling a period during which the transmittance is set at 0% by turning on the shutter of the transmittance changing section, a period during which the transmittance is set higher than 0% by turning off the shutter, and an angle of polarization of a liquid crystal when the shutter is off. <EOS>