PURPOSE: To provide a related schedule management device for enabling the change of related schedules accompanying the change of one schedule for the plural related schedules.

CONSTITUTION: This device is provided with a storage device for storing schedule data, an input device for inputting schedule contents, a display device for displaying the schedule contents and a schedule information updating device for updating and eliminating the schedule data. Then, the information of a related schedule ID 22 for making the plural schedules correspond to each other and related schedule accessory information 23 are set and the schedules of the same related schedule ID 22 are retrieved when the change of a certain schedule is generated. When they are present, a user is informed of that effect and the schedules are linked and changed.