A surveying instrument comprising: a monopod, which consists of one leg and is configured to be held by a worker, installed on a reference point and a surveying instrument main body provided at a known position from a lower end of said monopod and wherein a reference optical axis of an optical system of the surveying instrument main body is provided at a known angle to an axis of said monopod, wherein said surveying instrument main body has a first image pickup optical axis and a distance measuring optical axis, and said surveying instrument main body comprises a measuring direction image pickup module which acquires each first image including an object along said first image pickup optical axis, a distance measuring unit for measuring a distance to said object along said distance measuring optical axis, said surveying instrument main body includes an optical axis deflector in which said reference optical axis and said first image pickup optical axis have a known relationship and which deflects said distance measuring optical axis at an arbitrary angle ranging from 0° to a maximum deflection angle with respect to said reference optical axis, a measuring direction detecting module for detecting a measuring direction of said distance measuring optical axis deflected by said optical axis deflector, a time detector for generating a reference time signal and an arithmetic control module, wherein said arithmetic control module is configured to associate a distance measurement result of the measurement performed by said distance measuring unit with said reference time signal, to associate a measuring direction detected by said measuring direction detecting module with said reference time signal, to acquire said first image at a predetermined time interval by said measuring direction image pickup module, and to associate said acquired first image with said reference time signal, and wherein said arithmetic control module is configured: to detect an image displacement in each first image, wherein the image displacement consists in a vertical displacement, a lateral displacement, and a rotation of the image, to acquire in real time, based on the image displacement, rotation angles κ, ω, φ which represent a rotation displacement of the surveying instrument main body with respect to the lower end of said monopod, wherein κ is detected based on the vertical displacement of the image, ω is detected based in the lateral displacement of the image, and φ is detected as the rotation of the image, to associate said image displacement, a measuring direction detection result of said measuring direction detecting module, and a distance measurement result with each other based on said reference time signal, to calculate a measuring direction in the distance measurement based on said image displacement and said measuring direction detection result, and to determine a position of a measured part of said object. to acquire said first image at a predetermined time interval by said measuring direction image pickup module, and to associate said acquired first image with said reference time signal, and wherein said arithmetic control module is configured: to detect an image displacement in each first image, wherein the image displacement consists in a vertical displacement, a lateral displacement, and a rotation of the image, to acquire in real time, based on the image displacement, rotation angles κ, ω, φ which represent a rotation displacement of the surveying instrument main body with respect to the lower end of said monopod, wherein κ is detected based on the vertical displacement of the image, ω is detected based in the lateral displacement of the image, and φ is detected as the rotation of the image, to associate said image displacement, a measuring direction detection result of said measuring direction detecting module, and a distance measurement result with each other based on said reference time signal, to calculate a measuring direction in the distance measurement based on said image displacement and said measuring direction detection result, and to determine a position of a measured part of said object. to detect an image displacement in each first image, wherein the image displacement consists in a vertical displacement, a lateral displacement, and a rotation of the image, to acquire in real time, based on the image displacement, rotation angles κ, ω, φ which represent a rotation displacement of the surveying instrument main body with respect to the lower end of said monopod, wherein κ is detected based on the vertical displacement of the image, ω is detected based in the lateral displacement of the image, and φ is detected as the rotation of the image, to associate said image displacement, a measuring direction detection result of said measuring direction detecting module, and a distance measurement result with each other based on said reference time signal, to calculate a measuring direction in the distance measurement based on said image displacement and said measuring direction detection result, and to determine a position of a measured part of said object.