A connector comprising: a first connector comprising a first main terminal ; a second connector comprising a second main terminal ; and a fitting detection circuit configured to detect fitting of the first connector and the second connector , wherein the first connector further comprises a rotatable lever used for a fitting operation to the second connector by a rotation of the lever in a first rotation direction (Q1) and a fitting disengagement operation from the second connector by a rotation of the lever in a second rotation direction (Q2) opposite to the first rotation direction (Q1), the second connector comprises a boss having a protruding shape, characterized in that : the lever comprises a lock (70; 76) configured to lock, when the lock (70; 76) contacts the boss by the fitting disengagement operation, a rotation of the lever in a state where the fitting detection circuit does not detect the fitting and also in a state where the first main terminal and the second main terminal are connected, and the lock (70; 76) is configured to release locking of the rotation of the lever when an operation force of the fitting disengagement operation larger than a threshold is applied by the rotation of the lever in the second rotation direction (Q2) in a state where the lock (70; 76) contacts the boss . a first connector comprising a first main terminal ; a second connector comprising a second main terminal ; and a fitting detection circuit configured to detect fitting of the first connector and the second connector , wherein the first connector further comprises a rotatable lever used for a fitting operation to the second connector by a rotation of the lever in a first rotation direction (Q1) and a fitting disengagement operation from the second connector by a rotation of the lever in a second rotation direction (Q2) opposite to the first rotation direction (Q1), the second connector comprises a boss having a protruding shape, characterized in that : the lever comprises a lock (70; 76) configured to lock, when the lock (70; 76) contacts the boss by the fitting disengagement operation, a rotation of the lever in a state where the fitting detection circuit does not detect the fitting and also in a state where the first main terminal and the second main terminal are connected, and the lock (70; 76) is configured to release locking of the rotation of the lever when an operation force of the fitting disengagement operation larger than a threshold is applied by the rotation of the lever in the second rotation direction (Q2) in a state where the lock (70; 76) contacts the boss . the lever comprises a lock (70; 76) configured to lock, when the lock (70; 76) contacts the boss by the fitting disengagement operation, a rotation of the lever in a state where the fitting detection circuit does not detect the fitting and also in a state where the first main terminal and the second main terminal are connected, and the lock (70; 76) is configured to release locking of the rotation of the lever when an operation force of the fitting disengagement operation larger than a threshold is applied by the rotation of the lever in the second rotation direction (Q2) in a state where the lock (70; 76) contacts the boss . <EOS>