To obtain a method and an apparatus for measuring cycle (frequency) of a body to be measured driven at a high speed, which allow even a low-speed recording apparatus and display apparatus to record and display.

An output of cycle data of a sensor 2 which detects cycle (frequency) related to a body to be measured driven at a high speed, is latched at a latch circuit 6 and stored in a memory means 9. The cycle data read out from the memory means 9 are counted by a counter 11 based on a clock a cycle T of which can be freely selected by an optional frequency generation circuit 10. A string of pulses having an extended cycle is output and fed to a recording apparatus or the like.