A tire shape measuring system suitable for capturing an image (v1, v2, v3) of a line of light emitted to a surface of a relatively rotating tire and measuring the shape of the tire surface by detecting the shape using a light-section method on the basis of the captured image, comprising: line light emitting means (11, 12, 13) suitable for forming a plurality of separate light section lines (Ls1, Ls2, Ls3) on one surface of a plurality of surfaces of the tire by emitting a plurality of lines of light in a direction different from a direction in which the height of the tire surface is detected, each of the light section lines (Ls1, Ls2, Ls3) extending in a second direction perpendicular to a first direction representing a moving direction of the tire surface, areas occupied by the light section lines being shifted with respect to each other in the second direction; image capturing means suitable for capturing images (v1, v2, v3) of the separate light section lines (Ls1, Ls2, Ls3) formed on the one surface of the tire in directions in which chief rays (Li1, Li2, Li3) of the line light rays are specularly reflected by the tire surface at a predetermined amount of rotational movement of the tire; light section line coordinate detecting means suitable for individually detecting the coordinates of the light section lines (Ls1, Ls2, Ls3) corresponding to the coordinates of the images (v1, v2, v3) of the light section lines (Ls1, Ls2, Ls3) for each of the plurality of captured images captured by the image capturing means in accordance with the predetermined amount of rotational movement of the tire, wherein the coordinates of the light section lines (Ls1, Ls2, Ls3) are detected from each image of the plurality of the captured images in independent image processing target areas (A1, A2, A3), wherein the independent image processing target areas (A1, A2, A3) are pre-defined for the separate light section lines (Ls1, Ls2, Ls3) in a coordinate system of a captured image, wherein the independent image processing target areas (A1, A2, A3) are areas in which only the images (v1, v2, v3) of the light section lines (Ls1, Ls2, Ls3), which have a one-to-one correspondence with the image processing target areas (A1, A2, A3), are present; and surface shape calculating means suitable for calculating a distribution of the surface height of the tire in the first direction on the basis of the plurality of coordinates of the light section lines detected by the light section line coordinate detecting means. line light emitting means (11, 12, 13) suitable for forming a plurality of separate light section lines (Ls1, Ls2, Ls3) on one surface of a plurality of surfaces of the tire by emitting a plurality of lines of light in a direction different from a direction in which the height of the tire surface is detected, each of the light section lines (Ls1, Ls2, Ls3) extending in a second direction perpendicular to a first direction representing a moving direction of the tire surface, areas occupied by the light section lines being shifted with respect to each other in the second direction; image capturing means suitable for capturing images (v1, v2, v3) of the separate light section lines (Ls1, Ls2, Ls3) formed on the one surface of the tire in directions in which chief rays (Li1, Li2, Li3) of the line light rays are specularly reflected by the tire surface at a predetermined amount of rotational movement of the tire; light section line coordinate detecting means suitable for individually detecting the coordinates of the light section lines (Ls1, Ls2, Ls3) corresponding to the coordinates of the images (v1, v2, v3) of the light section lines (Ls1, Ls2, Ls3) for each of the plurality of captured images captured by the image capturing means in accordance with the predetermined amount of rotational movement of the tire, wherein the coordinates of the light section lines (Ls1, Ls2, Ls3) are detected from each image of the plurality of the captured images in independent image processing target areas (A1, A2, A3), wherein the independent image processing target areas (A1, A2, A3) are pre-defined for the separate light section lines (Ls1, Ls2, Ls3) in a coordinate system of a captured image, wherein the independent image processing target areas (A1, A2, A3) are areas in which only the images (v1, v2, v3) of the light section lines (Ls1, Ls2, Ls3), which have a one-to-one correspondence with the image processing target areas (A1, A2, A3), are present; and surface shape calculating means suitable for calculating a distribution of the surface height of the tire in the first direction on the basis of the plurality of coordinates of the light section lines detected by the light section line coordinate detecting means.