A defect detection apparatus comprising: a first control unit configured to: detect a defect that appears on an external appearance of a structure through imaging processing from external appearance image data that is generated by imaging the external appearance of the structure with a surveying instrument; calculate defect data relating to the defect detected by the first control unit by using coordinate data that is correlated with the external appearance image data; and initiate a remote control of the surveying instrument through a second control unit of the surveying instrument, wherein the first control unit is configured to cause the surveying instrument, on the basis of the remote control, to: define a measurement surface by performing distance measurement and angle measurement for each of at least two points of the structure, set a measurement range, for which the defect detection of the structure is performed, in the defined measurement surface, and wherein, in a case where a first imaging unit of the surveying instrument sequentially images the measurement range to capture the external appearance image data, when imaging a region including the outer edge of the measurement range, the second control unit either controls a first angle of view of the first imaging unit such that a region protruding from the outer edge is reduced or moves the first imaging unit such that a region protruding from the outer edge is reduced without changing the first angle of view. detect a defect that appears on an external appearance of a structure through imaging processing from external appearance image data that is generated by imaging the external appearance of the structure with a surveying instrument; calculate defect data relating to the defect detected by the first control unit by using coordinate data that is correlated with the external appearance image data; and initiate a remote control of the surveying instrument through a second control unit of the surveying instrument, wherein the first control unit is configured to cause the surveying instrument, on the basis of the remote control, to: define a measurement surface by performing distance measurement and angle measurement for each of at least two points of the structure, set a measurement range, for which the defect detection of the structure is performed, in the defined measurement surface, and wherein, in a case where a first imaging unit of the surveying instrument sequentially images the measurement range to capture the external appearance image data, when imaging a region including the outer edge of the measurement range, the second control unit either controls a first angle of view of the first imaging unit such that a region protruding from the outer edge is reduced or moves the first imaging unit such that a region protruding from the outer edge is reduced without changing the first angle of view. define a measurement surface by performing distance measurement and angle measurement for each of at least two points of the structure, set a measurement range, for which the defect detection of the structure is performed, in the defined measurement surface, and wherein, in a case where a first imaging unit of the surveying instrument sequentially images the measurement range to capture the external appearance image data, when imaging a region including the outer edge of the measurement range, the second control unit either controls a first angle of view of the first imaging unit such that a region protruding from the outer edge is reduced or moves the first imaging unit such that a region protruding from the outer edge is reduced without changing the first angle of view.