This paper make it clear that the two truss girders across the Daiya river were constructed across the Horomui river and across the Ikusyunbetsu river by Horonai railway in 1884-1885. We discovered unknown pictures of them taken in Meiji era and found that they have same shapes as the truss girders across the Daiya. We investigated official documents of Horonai railway to find out their date of construction and their specification. And we evaluate the value of them from a view point of civil engineering archaeology.