Geodetic observations were repeated several times in the KANTO-TOKAI district, Japan, during past a hundred years as follows; This is the first one of the papers in which the authors will give the results of unified net-adjustment, displacement vectors and calculated earth's strains in the KANTO -TOKAI district. The results of the net-adjustment for all observations are given in this paper with some discussions on the obtained accuracy that proved to be sufficient to detect crustal movements in the area.