This paper is the serial report concerning the continuous observation of crustal deformation at Inuyama since 1967. Digital records of crustal strain have been analyzed to separate the annual change of strain from the secular one. It has been found from the present analyses that the secular change in strain seems to be in accordance with both the horizontal displacement which was developed during the Mino-Owari earthquake in 1891 and the movement of geologic fault in the Quarternary epoch. The maximum shear strain rate developed by the tectonic stress in the NW-SE or W-E direction was found to be the order of 1×10_-6/year with the direction of about N10°W or N80°E . Geodetic data also show the same tendency. These facts suggest that the tectonic movement of the Quarternary epoch is still in the progressive stage. Some characteristics of the annual change in strain become clear. The clear and simple sinusoidal annual change is considered to be generated partly by the periodic thermal strain of rocks in the observational vault. However, most of the annual change which is amounting to 10_-6 in strain is thought to be generated by change of pore-water pressure in the fractured zone existing in the inner part of the vault. The mechanism of the annual variation in strain is explained by penetration of rain water into the fractured zone and discharge of pore-water out of it .