A positioning apparatus includes: a first positioning device for calculating a reception position of a GPS receiver with respect to each combination of satellites based on a pseudo distance from each positioning satellite to the reception position; a component error calculator for calculating an error of at least one component in a calculation result of the first positioning device; a pseudo distance error calculator for obtaining a relation equation between the error of the at least one component and an error of the pseudo distance, and for solving simultaneous equations comprising the relation equation so that the error of the pseudo distance with respect to each positioning satellite is calculated; and a second positioning device for correcting the reception position based on the error of the pseudo distance.