To provide a relay connector having a compact structure, and facilitating attachment and detachment of a lead wire, and connection length adjustment of the lead wire.

This relay connector for lead wire connection is provided with: a terminal housing part with an elastic connection terminal to the lead wire housed in a connector housing of the relay connector; a lead wire insertion hole for inserting the lead wire therein; and an attachment/detachment locking means of the inserted and connected lead wire. The attachment/detachment locking means of the lead wire is composed of: a ring-shaped coming-off preventing spring member having an elastic claw part elastically deforming along the insertion direction of the wire in its inside; and a pressing member for pressing the elastic claw part in the lead wire insertion direction and for releasing the lock of the lead wire.