PURPOSE: To obtain a protective relay for realizing easy and positive protection coordination with other machines.

CONSTITUTION: The protective relay for detecting fault in power system and outputting an interruption command signal comprises means 60 for inputting an arbitrary operating time characteristic curve, a processing means 61 for converting the curve inputted through the curve inputting means 60 into data, an input means 62 for taking in the data converted through the processing means 61, and means 63 for storing the data taken in through the input means 62. A microcomputer 23 outputting an operation output signal reads out an operating time table for the input current values from the memory means 63.