A connecting structure for a connector in which a male-side connector and a merging pipe are connected by screwing together a female screw having protrusions formed on the inner peripheral surface of a lock ring and a male screw comprising protrusions formed on the outer peripheral surface of the merging pipe is provided with engaging recess parts on the female screw and engaging projections on the outer peripheral surface of the merging pipe which are able to engage with the engaging recess parts whereby when the male screw and the female screw are screwed together to reach an appropriate screwed state, the engaging protrusions engage with the engaging recess parts.
