An object is to provide a screen image projection system for moving object having a smaller and/or lighter head-mounted part.
The present technology provides a screen image projection system for moving object (100) including a screen image projection device (101) mounted on a moving object, and an optical element for screen image display light diffraction (103) arranged in front of human eyes that move along with the moving object, the optical element for screen image display light diffraction (103) diffracting screen image display light projected from the screen image projection device (101) and causing the screen image display light to reach the human eyes. The present technology also provides a component of the screen image projection system and a method for projecting a screen image in the screen image projection system.