A gripping mechanism (3) includes a gripping roller (32) and a holder (31) that houses the gripping roller (32). A gripped portion (42) of a first component (4) is gripped between an outer surface of the gripping roller (32) and an inner surface of the holder (31) through action of gravity acting on the gripping roller (32). Preferably, the gripping roller (32) includes a core (321) that is cylindrical or columnar in shape and a covering section (322) that is an elastic body covering a circumferential surface of the core (321). Preferably, the covering section (322) has a circumferential surface with a friction coefficient greater than a friction coefficient of the circumferential surface of the core (321).