The present invention provides a standby power cut-off switch which is directly installed in electric products such as TV sets, audio systems, computers, etc., so that even when a power plug is connected to an electrical outlet, supply of an external power to the electric products through the plug is completely interrupted (i.e., double pole interruption) mechanically by means of an automatically controlled OFF signal so as to prevent the consumption of standby power, and in which a first input terminal and a first output terminal are first electrically connected to each other and then a second input terminal and a second output terminal are electrically connected to each other so that a double-pole switch eventually functions as a single-pole switch so as to allow an electrical contact between terminals to be made sequentially, thereby preventing a spark and an electrical shock to the electric product that may occur when the two poles of the switch concurrently come into close contact with a main body of the electric product during the powering on of the electric products.