A pattern shape measurement method includes acquiring image data of a target pattern obtained by irradiating an observation region of a sample with a charged particle or an electromagnetic wave, generating first contour point group data in which location information of a contour point of the target pattern extracted based on the image data and an index related to an orientation angle of a line connecting a center of the target pattern and the contour point from a reference line passing through the center of the target pattern are associated with each other, and generating, based on a weighting table in which the index and weight determined based on a standard deviation of location information of the contour point of the target pattern present in a direction of the orientation angle are associated with each other and stored, and the first contour point group data, second contour point group data according to the weight.