To obtain a method and an apparatus for measuring a light wave interference whereby a movement amount of an object moving at high speed can be correctly measured.

There are provided a moving mirror MX set movably on a measurement optical axis, a fixed mirror 206 fixed on a reference optical axis and, a processing apparatus 100. When a first interferometer (302, 300, 304, 306) among a plurality of interferometers becomes unable to measure, the processing apparatus makes a second interferometer (302, 300, 304, 308) continue the measurement. When the first interferometer (302, 300, 304, 306) turns from a measurement impossible state to a measurement possible state, the processing apparatus obtains an interference fringe degree related to a movement amount of the moving mirror MX on the basis of a measured value of the second interferometer (302, 300, 304, 308) and, resets a measured value of the first interferometer (302, 300, 304, 306) on the basis of the interference fringe degree and a phase measured by the first interferometer (300, 302, 304, 306).