A measurement method for measuring a shape of a test surface using an optical system that interferes test light from the test surface and reference light with each other, the measurement method comprising: a step of setting each of a plurality of measurement ranges so that a portion of the test surface is used as one measurement range and one measurement range overlaps a portion of at least another measurement range to form an overlap region; a step of measuring respective interference fringes between the reference light and the light from each of the plurality of measurement ranges; a step of obtaining a shape of the test surface at each of the measurement ranges from the measured respective interference fringes; and a step of calculating a shape of the test surface over the plurality of measurement ranges by stitching pieces of data of the shapes of the measurement ranges of the test surface, wherein the step of obtaining includes a step of obtaining the shape of the test surface in a first measurement range among the plurality of measurement ranges at a first resolution, and a step of obtaining the shape of the test surface in a second measurement range different from the first measurement range among the plurality of measurement ranges at a second resolution different from the first resolution, each of the first resolution and the second resolution is defined as a number of the pieces of data per unit length of the test surface, and a step of setting the first resolution and the second resolution in accordance with an interval of interference fringes measured in the measuring step of the first measurement range and the second measurement range, respectively, wherein, in the step of calculating, data of the shape of the test surface obtained in the first measurement range at the first resolution and data of the shape of the test surface obtained in the second measurement range at the second resolution are stitched. a step of setting each of a plurality of measurement ranges so that a portion of the test surface is used as one measurement range and one measurement range overlaps a portion of at least another measurement range to form an overlap region; a step of measuring respective interference fringes between the reference light and the light from each of the plurality of measurement ranges; a step of obtaining a shape of the test surface at each of the measurement ranges from the measured respective interference fringes; and a step of calculating a shape of the test surface over the plurality of measurement ranges by stitching pieces of data of the shapes of the measurement ranges of the test surface, wherein the step of obtaining includes a step of obtaining the shape of the test surface in a first measurement range among the plurality of measurement ranges at a first resolution, and a step of obtaining the shape of the test surface in a second measurement range different from the first measurement range among the plurality of measurement ranges at a second resolution different from the first resolution, each of the first resolution and the second resolution is defined as a number of the pieces of data per unit length of the test surface, and a step of setting the first resolution and the second resolution in accordance with an interval of interference fringes measured in the measuring step of the first measurement range and the second measurement range, respectively, wherein, in the step of calculating, data of the shape of the test surface obtained in the first measurement range at the first resolution and data of the shape of the test surface obtained in the second measurement range at the second resolution are stitched.