To provide a measuring apparatus, for the time difference of a signal, by which time difference information is output precisely from a detection signal having a phase difference.

Outputs of sensors 11A, 11B are input to a time-difference detection circuit 14 via amplifiers 12A, 12B and phase detectros 13A, 13B. The time-difference detection circuit 14 sequentially finds the input time difference between pulse signals which are output from the phase detectros 13A, 13B, and it outputs time difference information within a set range to a nest storage part 15 along a program which is controlled by a microcomputer or the like from a control part 18. The time difference information, within a prescribed time, which is stored in the storage part 15 is added in such a way that the number of samples becomes an even number on the basis of a command from the control part 18 in a computing part 16. Its added value is divided by pieces of information, in even numbers, which are sampled in a next division circuit 17, and average time difference information is calculated.