A connector includes lever pivotally mounted on a lateral wall of a male connector housing. When a female connector housing is inserted into the male connector housing, a cam follower projection formed on a cover is engaged with a cam groove formed on the lever. The lever is formed of four split pieces: a base plate, a second split piece, a third split piece, and an operating strip. For connecting or disconnecting the connectors, the lever can be expanded to maximize leverage. For storage, the lever can be contracted to minimize the amount of space occupied.