Provided is a retroreflective body 10 that has a first optical panel 16 in which orthogonal first and second inclined planes 11 and 12 are arranged on one surface side by side in a triangle wave pattern in cross section and a second optical panel 17 in which longitudinal grooves 14 having vertical planes 19 orthogonal to the first and second inclined planes 11 and 12, widened outwardly and each being serrated in cross section are formed in plurality. First and second inclined reflective planes 24 and 25 are formed on the first and second inclined planes 11 and 12, and vertical reflective planes 27 are formed on the vertical planes 19. In a volumetric image display apparatus 50, a half mirror 51 is arranged on this retroreflective body 10 in a crossed state.