1. An obstacle detecting method for detecting a presence of an obstacle to a moving body using a sensor mounted on the moving body, comprising: setting a movable area which is a surrounding area of the moving body and in which the moving body can move; arranging plural unconfirmed bodies over an entire area of the movable area as obstacle candidates as an initial state; and deleting the obstacle candidate which is determined not to be actually present as a result of detection by the sensor from the obstacle candidates arranged as the initial state.