Abstract: A clamp for a flat conductor is used in attaching the flat conductor to an attachment target. The clamp includes: a clip portion to be engaged with the attachment target; and a main body to hold the flat conductor. The clip portion has a first projection, the main body has a second projection, and the first projection and the second projection protrude to be opposed each other. The clip portion and the main body are configured to allow switching from an unlocked state to a locked state. The locked state restricts a relative movement between the clip portion and the main body in an axial direction of the flat conductor due to an engagement between the first projection and the second projection. The unlocked state allows the relative movement in both sides in the axial direction.