To provide a tide level observation alarm for automatically a risk alarm to tidal waves, etc. by observing a tide level without sending manpower to a hazard area and by collation with self-cumulative data in case of an earthquake.

The tide level observation alarm comprises a water level stabilization part, a water level detection part, an information analysis part including installation district characteristics and a transmission announcement part of the information and an alarm, etc. and whose installation place may be on the land or on the sea and which allows the installation place to be freely set.