A connector according to an aspect of the invention is a connector provided with a rear connector that includes a rear housing, and a front connector that includes a front housing and that is assembled to the rear connector; the rear housing contains a terminal of a cable end, and the front housing contains a mating terminal to be connected to the terminal; and the rear housing is provided with a checking window through which the terminal is exposed to outside and a voltage of the terminal can be checked, and a waterproof lid which closes the checking window in a sealed state.