A pattern measuring apparatus which can identify a kind of gaps formed by a manufacturing process having a plurality of exposing steps such as SADP, particularly, which can suitably access a gap even if a sample has the gap that is not easily accessed is disclosed. A feature amount regarding one end side of a pattern having a plurality of patterns arranged therein and a plurality of kinds of feature amounts regarding the other end side of the pattern are extracted from a signal detected on the basis of scanning of a charged particle beam. With respect to proper kinds of feature amounts among the plurality of kinds of feature amounts, the feature amount on one side of the pattern and that on the other end side of the pattern are compared. On the basis of the comparison, the kinds of spaces among the patterns are determined.