To provide a protective relay that can avoid unnecessary output if momentary noise is generated and operates in the case of determinative abnormality occurrence although conventionally a protective relay may perform unnecessary operation when an excessive short-time input is applied to a current single-input element.

A protective relay includes a function of locking a trip signal when a total of momentary values in one determination cycle does not exceed a threshold continuously as many times as a set determination frequency or larger even when an arithmetic processing part makes an operation determination and an operation is determined.