To detect and record an event occurring to an input signal whose electric characteristic is changed by a temporal factor.

An event recording-device includes: a time-piece part 4 for outputting date/time data Dt indicating the current date/time; and a storage part 6 for storing plural thresholds Wth correlated with a recording condition related to a date/time. Further, a process part 8 performs: a clock-time obtainment process for obtaining date/time data Dt from the time-piece part 4 every time effective power W is measured; a recording-condition specifying-process for specifying, as an effective recording-condition, a recording-condition related to a date/time indicated by the date/time data Dt obtained in the clock-time obtainment process from among plural recording-conditions; and an occurrence state recording-process for detecting the occurrence start and occurrence stop of an event related to an alternate-current signal S1 by comparing the measured effective power W with the threshold Wth and recording in the storage part 6 an occurrence state of either one of the detected occurrence start and occurrence stop, on the basis of a threshold Wth corresponding to the effective recording-condition specified in the recording-condition specifying-process.