Abstract: A connector in which an electrical contact portion of a female terminal has a tubular portion corresponding in shape to a terminal receiving chamber in a connector housing. A slit is formed in the tubular portion, and extends in a direction of insertion of the terminal. An engagement projection which is slidably fitted in the slit is formed on an inner surface of the terminal receiving chamber. When the female terminal is inserted in a proper manner, the engagement projection is fitted into the slit in the tubular portion, and therefore the female terminal is completely inserted into the terminal receiving chamber. On the other hand, when the female terminal is inserted in a wrong manner, the front end of the tubular portion abuts against the engagement projection, thereby preventing the insertion of the female terminal.