A tire surface inspecting method comprising the steps of: placing a line camera at a predetermined position with respect to a surface of a tire to be inspected; setting an objective line on a part of the surface of the tire; projecting light toward the objective line; forming an image of a part of the surface of the tire corresponding to the objective line by the line camera; and analyzing images formed by the line camera to inspect the surface of the tire, characterised in that: tire surface inspecting method further comprises the steps of: providing a first illuminating means including paired first light projectors (11 a, 11 b) for projecting light toward the objective line from opposite sides, respectively, with respect to the objective line, and a second illuminating means including paired second light projectors (12a, 12b) for projecting light toward the objective line respectively from opposite sides in an illuminating direction different from that in which the first illuminating means illuminates; alternately operating the first and second illuminating means to alternately illuminate a part of the surface of the tire corresponding to the objective line; operating the line camera to form an image of the part of the surface of the tire corresponding to the objective line for analysis in synchronism with the alternate illuminating operations of the first and second illuminating means; and repeating the step of alternately operating the first and second illuminating means and the step of operating the line camera with the objective line on the surface of the tire which is changed in position. placing a line camera at a predetermined position with respect to a surface of a tire to be inspected; setting an objective line on a part of the surface of the tire; projecting light toward the objective line; forming an image of a part of the surface of the tire corresponding to the objective line by the line camera; and analyzing images formed by the line camera to inspect the surface of the tire, characterised in that: tire surface inspecting method further comprises the steps of: providing a first illuminating means including paired first light projectors (11 a, 11 b) for projecting light toward the objective line from opposite sides, respectively, with respect to the objective line, and a second illuminating means including paired second light projectors (12a, 12b) for projecting light toward the objective line respectively from opposite sides in an illuminating direction different from that in which the first illuminating means illuminates; alternately operating the first and second illuminating means to alternately illuminate a part of the surface of the tire corresponding to the objective line; operating the line camera to form an image of the part of the surface of the tire corresponding to the objective line for analysis in synchronism with the alternate illuminating operations of the first and second illuminating means; and repeating the step of alternately operating the first and second illuminating means and the step of operating the line camera with the objective line on the surface of the tire which is changed in position. tire surface inspecting method further comprises the steps of: providing a first illuminating means including paired first light projectors (11 a, 11 b) for projecting light toward the objective line from opposite sides, respectively, with respect to the objective line, and a second illuminating means including paired second light projectors (12a, 12b) for projecting light toward the objective line respectively from opposite sides in an illuminating direction different from that in which the first illuminating means illuminates; alternately operating the first and second illuminating means to alternately illuminate a part of the surface of the tire corresponding to the objective line; operating the line camera to form an image of the part of the surface of the tire corresponding to the objective line for analysis in synchronism with the alternate illuminating operations of the first and second illuminating means; and repeating the step of alternately operating the first and second illuminating means and the step of operating the line camera with the objective line on the surface of the tire which is changed in position. providing a first illuminating means including paired first light projectors (11 a, 11 b) for projecting light toward the objective line from opposite sides, respectively, with respect to the objective line, and a second illuminating means including paired second light projectors (12a, 12b) for projecting light toward the objective line respectively from opposite sides in an illuminating direction different from that in which the first illuminating means illuminates; alternately operating the first and second illuminating means to alternately illuminate a part of the surface of the tire corresponding to the objective line; operating the line camera to form an image of the part of the surface of the tire corresponding to the objective line for analysis in synchronism with the alternate illuminating operations of the first and second illuminating means; and repeating the step of alternately operating the first and second illuminating means and the step of operating the line camera with the objective line on the surface of the tire which is changed in position.