An electrical connection device includes a first connector and a second connector capable of being mechanically and electrically connected to the first connector. A lock mechanism can lock the connection between the first and second connectors. The first connector has a cover capable of covering a connecting region between the first and second connectors. The second connector has an unlock device operable to unlock the lock mechanism. The unlock device is positioned not to interact with the cover when the first and second connectors are connected to each other.