A measurement system (1,1'), for measuring a member spacing and a member thickness of a construction member at a construction work site, comprising a scanner device including a distance-measuring unit configured to perform scanning a distance and an angle to a measurement point by measuring a time taken for reciprocation between a distance-measuring light to the measurement point, one or more construction members constituting a structure are regarded as a measuring target, the measurement system (1,1') is configured to: scan three-dimensional coordinates of two or more designated points designated by a measurement worker on a three-dimensional space with respect to the measuring target, calculate a three-dimensional measurement line connecting the designated points on the three-dimensional space and line-scan on the three-dimensional measurement line by outputting the distance-measuring light, extract only point cloud data within a predetermined distance range from the three-dimensional measurement line on the three-dimensional space, and by using the extracted point cloud data, determine an area via which points are away from each other as a member spacing of the measuring target, and determine an area of dense points as a member thickness of the measuring target, and calculate numerical values of the member spacing and/or the member thickness, and display the numerical values of the member spacing and/or the member thickness on a display unit. a scanner device including a distance-measuring unit configured to perform scanning a distance and an angle to a measurement point by measuring a time taken for reciprocation between a distance-measuring light to the measurement point, one or more construction members constituting a structure are regarded as a measuring target, the measurement system (1,1') is configured to: scan three-dimensional coordinates of two or more designated points designated by a measurement worker on a three-dimensional space with respect to the measuring target, calculate a three-dimensional measurement line connecting the designated points on the three-dimensional space and line-scan on the three-dimensional measurement line by outputting the distance-measuring light, extract only point cloud data within a predetermined distance range from the three-dimensional measurement line on the three-dimensional space, and by using the extracted point cloud data, determine an area via which points are away from each other as a member spacing of the measuring target, and determine an area of dense points as a member thickness of the measuring target, and calculate numerical values of the member spacing and/or the member thickness, and display the numerical values of the member spacing and/or the member thickness on a display unit. scan three-dimensional coordinates of two or more designated points designated by a measurement worker on a three-dimensional space with respect to the measuring target, calculate a three-dimensional measurement line connecting the designated points on the three-dimensional space and line-scan on the three-dimensional measurement line by outputting the distance-measuring light, extract only point cloud data within a predetermined distance range from the three-dimensional measurement line on the three-dimensional space, and by using the extracted point cloud data, determine an area via which points are away from each other as a member spacing of the measuring target, and determine an area of dense points as a member thickness of the measuring target, and calculate numerical values of the member spacing and/or the member thickness, and display the numerical values of the member spacing and/or the member thickness on a display unit.