Prestressed concrete continuous box-girder bridge with hinge at mid span is one of the popular type of bridge, and many bridges of this type have been constructed in highway. It is evaluated in its cost performance in construction. On the other hand, there are some reports on its repairment for reduction of its function such as its large time dependent displacement due to creep and shrinkage in concrete. This paper describes the result of investigation about certain factors which affect on such displacement by the use of an analytical method as well as field observations.