PURPOSE: A linearity management system of a rod bridge is provided to calculate a correction value of case tension by calculating the degree of separation of the rod bridge under construction from target linearity. CONSTITUTION: A GPS receiver(310) receives position coordinate data of a reference point from GPS satellites. A measurement error acquiring unit(320) acquires a measurement error by comparing the position coordinate data of the reference point with position coordinate data of a reference point which is measured by a separate measuring method. A storing unit(330) stores the measurement error. A wired and wireless communications unit(340) receives the position coordinate data of the top of a pylon from a pylon top position data collecting unit. A correction process part(350) applies the measurement error to the position coordinate data of the top of the pylon and corrects the position coordinate data. A linearity management unit(360) calculates the degree of separation from target linearity and calculates a correction value of cable tension of a rod bridge. [Reference numerals] (310) GPS receiver; (320) Measurement error acquiring unit; (330) Storing unit; (340) Wired and wireless communications unit; (350) Correction process part; (360) Linearity management unit; (370) Power supply unit
