A high voltage safety device for a high voltage battery is provided, which comprises: a switch terminal forming a switch of an electric circuit for a high voltage portion and protruding to be fitted in a position hole of a high voltage cover; and a plug forming the electric circuit by connecting the switch when being fitted on the switch terminal and having a size occupying a portion of the high voltage cover. With the safety device, it is possible to prevent unintended separation of a high voltage cover without using a relatively expensive interlock, thereby ensuring safety.