A connector device comprising: a connector that includes a housing, a lever, and a main terminal; and a mating connector that includes a mating housing and a mating main terminal, wherein a guide groove is formed on one of the lever and the housing and a guide shaft is formed on the other, the lever is attached to the housing so that the guide shaft is positioned on the guide groove and the lever is thereby capable of rotating between a first position and a second position and sliding between the second position and a third position, the first position, the second position and the third position being positions for the lever to take with respect to the housing, one of a cam groove and a driven boss, the cam groove and the driven boss constituting a cam mechanism, is formed on the lever and the other is formed on the mating housing, when the connector of which the lever is on the first position is on a fitting preparation position with respect to the mating connector, a rotation of the lever to the second position causes the connector to be drawn to a fitting position by the cam mechanism, the fitting position being closer to the mating connector than the fitting preparation position, connecting the main terminal and the mating main terminal with each other by time when the lever reaches at least the second position, and when the connector of which the lever is on the second position is on the fitting position with respect to the mating connector, a rotation of the lever to the first position causes the connector to be pushed back to the fitting preparation position by the cam mechanism, releasing a connection between the main terminal and the mating main terminal, wherein the housing includes a flange portion (36, 37), the mating housing includes a mating flange portion (115, 116), the lever includes a groove portion (45, 46) that extends in a direction of the sliding, characterized in that when the lever of the connector that is on the fitting position with respect to the mating connector is slid from the second position to the third position, the flange portion (36, 37) and the mating flange portion (115, 116) are both accommodated in the same groove portion (45, 46) in a manner to be appressed against each other and thereby are held by the lever, and when the lever of the connector that is on the fitting position with respect to the mating connector is slid from the third position to the second position, holding of the flange portion (36, 37) and the mating flange portion (115, 116) by the lever is released. a connector that includes a housing, a lever, and a main terminal; and a mating connector that includes a mating housing and a mating main terminal, wherein a guide groove is formed on one of the lever and the housing and a guide shaft is formed on the other, the lever is attached to the housing so that the guide shaft is positioned on the guide groove and the lever is thereby capable of rotating between a first position and a second position and sliding between the second position and a third position, the first position, the second position and the third position being positions for the lever to take with respect to the housing, one of a cam groove and a driven boss, the cam groove and the driven boss constituting a cam mechanism, is formed on the lever and the other is formed on the mating housing, when the connector of which the lever is on the first position is on a fitting preparation position with respect to the mating connector, a rotation of the lever to the second position causes the connector to be drawn to a fitting position by the cam mechanism, the fitting position being closer to the mating connector than the fitting preparation position, connecting the main terminal and the mating main terminal with each other by time when the lever reaches at least the second position, and when the connector of which the lever is on the second position is on the fitting position with respect to the mating connector, a rotation of the lever to the first position causes the connector to be pushed back to the fitting preparation position by the cam mechanism, releasing a connection between the main terminal and the mating main terminal, wherein the housing includes a flange portion (36, 37), the mating housing includes a mating flange portion (115, 116), the lever includes a groove portion (45, 46) that extends in a direction of the sliding, characterized in that when the lever of the connector that is on the fitting position with respect to the mating connector is slid from the second position to the third position, the flange portion (36, 37) and the mating flange portion (115, 116) are both accommodated in the same groove portion (45, 46) in a manner to be appressed against each other and thereby are held by the lever, and when the lever of the connector that is on the fitting position with respect to the mating connector is slid from the third position to the second position, holding of the flange portion (36, 37) and the mating flange portion (115, 116) by the lever is released.