[Problem] To provide a female-side connector having a locking mechanism by which a favorable fastening force is consistently obtained. [Solution] In a female-side connector (10), the central axis (13) of a trough (15) in a male screw thread part (12) of a female-side locking part (41) for engaging with a female screw thread part (23) of a male-side locking part (42) in a male-side connector (20) intersects at a predetermined angle relative to the central axis (14) of a crest (16).
