For the purpose of multipoint dynamic displacement measurement, we investigate application of time division multiplexing (TDM) technique to a fiber optic interferometer, in which the phase of the reference light is modulated and the channels of the probe light are switched in synchronization with the modulation frequency. In the proposed TDM method, measurements at multiple points are synchronized without any complicated control. By changing the duty ratio of the switching time, bandwidth allocated for each channel of measurement is changed arbitrarily. Simulation and proofof-concept experiment confirm the principle and the effectiveness of the proposed method.