An annunciation method includes the steps of obtaining first position information as position information of a place where a first object is located, obtaining second position information as position information of a place where a second object is located, obtaining third position information as position information of a place where a third object is located, setting the first object and the second object as a first group when a distance between the first object and the second object calculated based on the first position information and the second position information is smaller than or equal to a first threshold value, obtaining fourth position information representing a position of the first group, and performing annunciation when a distance between the third object and the first group calculated based on the third position information and the fourth position information is smaller than a second threshold value.