To provide an overcurrent warning device, with an needless-power detecting function, by which whether a user turns off the power supply of an electric apparatus not used during one's absence without forgetting can be detected.

In the overcurrent warning device 1 with the needless-power detecting function, a setting switch 7 is pressed in a state that all power supplies of electric apparatuses which are not used during the absence of the user are turned off. A consumed current value at this time is set in a central computing part 4 as a setting current value, and the needless-power detecting function is set, When the needless-power detecting function is set, the setting current value and the consumed current value are compared by the central computing part 4. When the consumed current value is higher than the setting current value, an LED 5 is turned on, and it is detected that the power supply of a needless electric apparatus is not turned off. When the consumed current value is lower than the setting current value, the LED 5 is not turned on, and it is detected that the power supply of the needless electric apparatus is turned off.