A coupling/uncoupling mechanism (10A) according to the present invention maintains, when a male coupling body (30A) is coupled to a female coupling body (20A), a condition that the male coupling body (30A) is inserted in an insertion space (SO) and the other end of a lever member (22) is in a position in proximity to the insertion space (SO), so that an engaging surface (23a) of an engaging member (23) is contacted with an engageable surface (31a) of the male coupling body (30A). When the male coupling body (30A) and the female coupling body (20A) is uncoupled, the other end of the lever member (22) moves to a direction to be apart from the insertion space (SO), so that the engaging surface (23a) moves toward a withdrawing direction (D2). This allows releasing the contacting of the engaging surface (23a) with the engageable surface (31a). This provides that sufficient fastening force can be achieved with a simple configuration and the coupling status can be retained with a smaller force as compared with such a fastening force, and further, a recombination can be easily achieved even after a separation is made.