Here the authors made a consideration on the method of tracing the path of propagation of tunamis caused by earthquakes. The differential equation of the path was obtained for the case in which the position of the observing station and that of the epicentre of the earthquake are given. As an example of solution of the differential equation, a particular case was treated in which the profile curve of the bottom surface of the sea is a parabola. The path thus obtained is a circular arc. This method was applied to an actual case. The result suggests its applicabihty to some other similar cases.