An augmentation information adjustment unit (102) reduces an amount of information in augmentation information by combining: update cycle adjustment processing (1021) to set an update cycle of the augmentation information to be an integer multiple of a predetermined update cycle; geographic interval error value adjustment processing (1022) to reduce the number of geographic interval error values by selecting from among a plurality of the geographic interval error values each of which is an error at every predetermined geographic interval out of a plurality of error values, a geographic interval error value at every geographic interval that is an integer multiple of the predetermined geographic interval; and bit count adjustment processing (1023) to reduce a bit count of the error value for each error value. An augmentation information output unit (103) outputs, to an output destination, augmentation information after being reduced in the amount of information by the augmentation information adjustment unit (102).