A reminder notification system includes a first terminal and a second terminal which include a reminder notification unit configured to provide a reminder of a predetermined task. The first terminal includes a task registration setting unit configured to register and set the predetermined task as a target task. The first terminal and the second terminal each include a task information share unit configured to share the target task that is registered and set in the task registration setting unit between the first terminal and the second terminal. At least one of the first terminal and the second terminal includes a notification terminal setting unit configured to set any of the first terminal and the second terminal as a notification terminal configured to provide the reminder on the basis of content of the target task when executable conditions of the target task are satisfied.