The invention concerns a connecting structure for a connector with which it is possible to prevent the appearance of cracks and liquid leakage. The problem is solved by a connecting structure (A) for a connector in which a male-side connector (20) and a merging pipe (14) are connected by screwing together a female screw (26) comprising protrusions formed on the inner peripheral surface of a lock ring (25) and a male screw (17) comprising protrusions formed on the outer peripheral surface of the merging pipe (14) is provided with engaging recess parts (27) on the female screw (26) and engaging projections (18) on the outer peripheral surface of the merging pipe (14) which are able to engage with the engaging recess parts (27). Then, when the male screw (17) and the female screw (26) are screwed together to reach an appropriate screwed state, the engaging protrusions (18) engage with the engaging recess parts (27).
