Abstract: The invention is directed to an apparatus for measuring the thickness of flexible sheet material such as cloth, carpet, paper, sheet metal or plastic, for example. The apparatus includes a break member over which the sheet material is folded and advances. The apparatus also includes a light source and a light sensor that are preferably included in a laser scan micrometer. The apparatus also includes a carriage movable in a direction parallel to the break member. The light source is mounted to the carriage so that it opposes one side of the break member, and casts a shadow whose linear extent is indicative of the sheet material's thickness. The light sensor is mounted to the carriage on the opposite side of the break roller from that on which the light source is positioned. The light sensor and the light source can thus be used to generate sheet material thickness data at any predetermined position across the sheet material.