A projection display device comprises: a display device; an optical system configured to form a regular optical path (L1, L2, L3, and L4) to project light toward a projection position as a display image, the light being emitted from the display device; and a shielding plate, wherein the optical system comprises a pair of mirrors (21, 22) provided on the regular optical path (L1, L2, L3, and L4), one of the mirrors being configured to provide an optical path convergence point, at which the light converges, on the regular optical path (L1, L2, L3, and L4), wherein the projection display device is configured such that a position of a mirror surface of at least one of the pair of mirrors (21, 22) is adjustable in accordance with an eye point of a user who visually recognizes the display image so as to project the light that has passed the optical path convergence point via the pair of mirrors (21, 22) toward the projection position that corresponds to the eye point, characterized in that the other mirror of the pair of mirrors (21, 22) is provided at a position corresponding to the optical path convergence point, the shielding plate is configured to prevent the light from reaching the projection position via a different optical path different from the regular optical path (L1, L2, L3, and L4), and the shielding plate is provided such that the shielding plate does not interfere with the regular optical path (L1, L2, L3, and L4) between the pair of mirrors (21, 22) and such that the shielding plate interferes with the different optical path along which the light travels toward the projection position without being reflected by the pair of mirrors (21, 22). a display device; an optical system configured to form a regular optical path (L1, L2, L3, and L4) to project light toward a projection position as a display image, the light being emitted from the display device; and a shielding plate, wherein the optical system comprises a pair of mirrors (21, 22) provided on the regular optical path (L1, L2, L3, and L4), one of the mirrors being configured to provide an optical path convergence point, at which the light converges, on the regular optical path (L1, L2, L3, and L4), wherein the projection display device is configured such that a position of a mirror surface of at least one of the pair of mirrors (21, 22) is adjustable in accordance with an eye point of a user who visually recognizes the display image so as to project the light that has passed the optical path convergence point via the pair of mirrors (21, 22) toward the projection position that corresponds to the eye point, characterized in that the other mirror of the pair of mirrors (21, 22) is provided at a position corresponding to the optical path convergence point, the shielding plate is configured to prevent the light from reaching the projection position via a different optical path different from the regular optical path (L1, L2, L3, and L4), and the shielding plate is provided such that the shielding plate does not interfere with the regular optical path (L1, L2, L3, and L4) between the pair of mirrors (21, 22) and such that the shielding plate interferes with the different optical path along which the light travels toward the projection position without being reflected by the pair of mirrors (21, 22).