The 1st order triangulation network across the Suruga Bay, Honshu, Japan was surveyed three times in 1883/1891, 1931, 1973 respectively. The earth's horizontal strains were deduced from the survey data for different three periods, 1833/1891-1931, 1931-1973, and 1883/1891-1973. The results of calculations show that the earth's surface is com pressed along almost NW-SE direction throughout the whole period. Compression axis is directed to N46°W and maximum shear strain velocity is 3.6×10
-7/yr in the northern part of the Suruga Bay. These values are N52.5°W and 1.6×10
-7/yr in the middle of the Suruga Bay, N28°W and 3.1×10
-7/yr in the southern Suruga Bay, respectively. The earth's strain that is accumulated during the period from 1854, year of Ansei Tokai earthquake, to the present in the Suruga Bay is estimated by using the obtained strain velocity.
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