A mobile device comprises a communicator configured to communicate with another communication device; an acceleration sensor configured to detect an acceleration value; a direction sensor configured to detect a change of a direction of the mobile device; and at least one controller configured to determine number of steps of a user of the mobile device based on the acceleration value, and a direction of walking of the user based on the change of the direction of the mobile device to perform notification to the other communication device through the communicator when cumulative number of steps of the walking of the user in one of directions exceeds a first value.