PURPOSE: To obtain an electric power measuring apparatus for continuously measure plural kinds of electric energy by the reduced number of parts and convenient in handling, by using a pulse width modulation circuit and a multi-stage output delay circuit in common.

CONSTITUTION: A pulse width duty cycle signal outputted from a pulse width modulation circuit 22 is outputted at random so as to provide time delay by a multi-stage output delay circuit 24 and the aforementioned randomly delayed pulse width duty cycle signal is selected by the output of a delay time setting circuit 23 for fabricating a delay time by using either one of load voltage and a consumption current or both of them to be introduced into each time sharing multiple circuits 33AW33C to perform multiplication. By this method, circuits provided to the previous stage side of the time sharing multiple circuits 33AW 33C, that is, the pulse width modulation circuit, the multi-stage output delay circuit 24 or the like can be used in common and, by this mechanism, an electric power measuring apparatus for continuously measuring plural kinds of electric energy by the reduced number of parts and convenient in handling can be obtained.