A video display system (1,101) comprising: a marker having a reference pattern; a first polarizing filter having a first polarization characteristic; a video display device (2,102) including a camera configured to capture the marker via the first polarizing filter, and a display unit having a light transmission property allowing an actual video to be seen therethrough; a second polarizing filter having a second polarization characteristic contrary to the first polarizing filter; and an amount-of-change calculation unit configured to calculate an amount of change between a first image obtained such that the camera captures the reference pattern in a first attitude and a second image obtained such that the camera captures the reference pattern in a second attitude, and calculate an amount of change in an attitude in accordance with the amount of change between the first image and the second image; wherein the first polarizing filter and the second polarizing filter are arranged between the marker and the display unit in a state in which the marker and the display unit are opposed to each other; and wherein the display unit includes a right-eye display unit and a left-eye display unit and is configured to display a right-eye image on the right-eye display unit and a left-eye image on the left-eye display unit based on an image generated according to the amount of change in the attitude. a marker having a reference pattern; a first polarizing filter having a first polarization characteristic; a video display device (2,102) including a camera configured to capture the marker via the first polarizing filter, and a display unit having a light transmission property allowing an actual video to be seen therethrough; a camera configured to capture the marker via the first polarizing filter, and a display unit having a light transmission property allowing an actual video to be seen therethrough; a second polarizing filter having a second polarization characteristic contrary to the first polarizing filter; and an amount-of-change calculation unit configured to calculate an amount of change between a first image obtained such that the camera captures the reference pattern in a first attitude and a second image obtained such that the camera captures the reference pattern in a second attitude, and calculate an amount of change in an attitude in accordance with the amount of change between the first image and the second image; calculate an amount of change between a first image obtained such that the camera captures the reference pattern in a first attitude and a second image obtained such that the camera captures the reference pattern in a second attitude, and calculate an amount of change in an attitude in accordance with the amount of change between the first image and the second image; wherein the first polarizing filter and the second polarizing filter are arranged between the marker and the display unit in a state in which the marker and the display unit are opposed to each other; and wherein the display unit includes a right-eye display unit and a left-eye display unit and is configured to display a right-eye image on the right-eye display unit and a left-eye image on the left-eye display unit based on an image generated according to the amount of change in the attitude.