Safety diagnostic bridge superstructure measuring device is disclosed interval, the diagnostic safety bridge superstructure distance measuring device, a bar member; A sheet member that is the other end connected to one end of the bar member; The length along the said longitudinal direction of the bar member arranged so as to extend in a direction, movably guide and arranged such that the extension is bent in a direction of the first orthogonal direction perpendicular to said longitudinal doedaga extending along the longitudinal direction a housing including a sheet member in the longitudinal direction with the first movable along a direction perpendicular to the guide members to guide parts; And a linear portion which comprising a driving force transmission unit for transmitting a driving force to move along the longitudinal direction of the bar member to the bar member, wherein the housing part facing the longitudinal direction of the bar member and the seat member position, and the first right angle the head and includes a bend that part of the position, the linear portion connected to connected to the bent portion housing blocks and the connecting housing block of the other end directly or indirectly to the base housing block which is connected to the seat member the inclusion, and it is possible, in one or more expansion between the housing block connected to the housing block and said base block housing.