Electronic tide meter

To dynamically display a tide graph. A tide level calculation unit obtains a tide level at an interval of a time set by a display time setting unit on the basis of a date/time inputted from a date setting unit, a point inputted by a point setting unit and tidal component data at this point. Then, a tide level difference calculation unit obtains a tide level difference from a difference between a maximum value and a minimum value of tide levels, a tide level range displayed by one segment is obtained by dividing this tide level difference by a segment count along a tide-level-axis, and the tide level range is changed. Accordingly, dynamic display utilizing a display area of a display unit to the full can be attained.