Since a rotary connector B in which lock operation is released is mounted onto a steering device, in this mounting operation, the neutral rotation positions of both housings are shifted, resulting in wrong mounting. Therefore, there is provided a rotary connector permitting reliable mounting. A lock member is integrally formed of an arm portion, a finger-hook portion, a coupling portion, and a fixing portion, the fixing portion having a thin portion and a fixing remaining portion wherein, in a locked state, the fixing remaining portion is held at a locking portion of a first housing, the coupling portion is engaged with a rotation restraint portion, the arm portion is provided along a top surface, and the finger-hook portion is protruded outwardly of an outer cylindrical portion, and in an unlocked state, the finger-hook portion is folded so as to be close to the outer cylindrical portion, thereby separating the arm portion from the thin portion while the fixing remaining portion remains held in the locking portion of the first housing.