PURPOSE: A digital tide time clock is provided to inform high tide time and height and low tide time and height by collecting marine information including geographical information and meridian transit time. CONSTITUTION: An inputting unit(100) receives a local code number from a user and collects marine information including global positioning system(GPS) information, a current time, coast geographical information, and local information. A local position setting unit(200) sets local code numbers based on local positions and reference position information as a database and analyzes the GPS information for obtaining corresponding local code number. A calculating unit(300) calculates high tide time and height and low hide time and height.
