A three-dimensional image display device comprising: an image display screen configured to display a two-dimensional image of an object to be observed; a motion parallax amount measurement unit configured to measure a to-display-screen parallax angle Θ1 and a to-display-screen separation distance Le with respect to the image display screen; and a display unit configured to select, from a plurality of two-dimensional images, a two-dimensional image of the object to be observed that has rotated by an angle ΔΘ corresponding to the to-display-screen parallax angle Θ1, and transmit the two-dimensional image to the image display screen, wherein each of the plurality of two-dimensional images is associated with three-dimensional information, the three-dimensional information includes at least the rotational angle ΔΘ and a virtual separation distance Lo, and when the two-dimensional image is selected by the display unit, the rotational angle ΔΘ of the object to be observed is determined on the basis of the following formula: ΔΘ = Θ 1 × Le / Lo + Le, wherein the to-display-screen parallax angle Θ1 is a motion parallax angle of an observer with respect to the image display screen and is identified by the motion parallax amount measurement unit, the to-display-screen separation distance Le is a separation distance between an eye of the observer and the image display screen and is identified by the motion parallax amount measurement unit, the virtual separation distance Lo is a virtual separation distance between the object to be observed and the image display screen and is determined when the image is generated, and the rotational angle ΔΘ is a rotational angle of the object to be observed and is determined on the basis of Θ1, Le, and Lo that are known. an image display screen configured to display a two-dimensional image of an object to be observed; a motion parallax amount measurement unit configured to measure a to-display-screen parallax angle Θ1 and a to-display-screen separation distance Le with respect to the image display screen; and a display unit configured to select, from a plurality of two-dimensional images, a two-dimensional image of the object to be observed that has rotated by an angle ΔΘ corresponding to the to-display-screen parallax angle Θ1, and transmit the two-dimensional image to the image display screen, wherein each of the plurality of two-dimensional images is associated with three-dimensional information, the three-dimensional information includes at least the rotational angle ΔΘ and a virtual separation distance Lo, and when the two-dimensional image is selected by the display unit, the rotational angle ΔΘ of the object to be observed is determined on the basis of the following formula: ΔΘ = Θ 1 × Le / Lo + Le, wherein the to-display-screen parallax angle Θ1 is a motion parallax angle of an observer with respect to the image display screen and is identified by the motion parallax amount measurement unit, the to-display-screen separation distance Le is a separation distance between an eye of the observer and the image display screen and is identified by the motion parallax amount measurement unit, the virtual separation distance Lo is a virtual separation distance between the object to be observed and the image display screen and is determined when the image is generated, and the rotational angle ΔΘ is a rotational angle of the object to be observed and is determined on the basis of Θ1, Le, and Lo that are known.