1. A measurement method for measuring an outline of a pattern from an image of a sample including the pattern obtained by a charged particle beam apparatus, comprising: a first step of extracting edge points configuring the outline of the pattern; a second step of obtaining a first brightness profile in the vicinity of a first edge point among the edge points; a third step of obtaining a second brightness profile in the vicinity of a second edge point among the edge points; a fourth step of obtaining a third brightness profile in the vicinity of a third edge point among the edge points; a fifth step of obtaining an evaluation value of a shape of the first brightness profile, based on the first brightness profile and the second and third brightness profiles that are obtained; and a sixth step of performing an outline correction of the pattern of the first edge point based on the evaluation value.