Provided are a pattern measuring apparatus and a computer program which determine whether a gap formed in a sample (201) is a core gap (211) or a spacer gap (212). The secondary electron profile of the sample (201) is acquired, the feature quantities of the secondary electron profile at the positions of edges (303, 305) are detected, and based on the detected feature quantities, whether each gap adjacent to each of the edges (303, 305) is the core gap (211) or the spacer gap (212) is determined. Furthermore, the waveform profile of the spacer (207) is previously stored, the secondary electron profile of the sample (201) is acquired, a matching degree of the secondary electron profile and the stored waveform profile at the position of each spacer (207) is detected, and based on the detected matching degree, whether the each gap adjacent to each spacer (207) is the core gap (211) or the spacer gap (212) is determined.