CLAMP AND WIRE HARNESS

A clamp and a wire harness capable of being easily installed on a fixation portion are provided. The clamp includes the holder , which holds the outer sheath accommodating an electric wire, and the fixed portion , which is connected to the holder and fixed to the vehicle body panel P. The fixed portion includes the insertion groove , into which the columnar fastener B on the vehicle body panel P is inserted. The insertion groove extends through the fixed portion in the X-axis direction. The insertion groove is shaped so as to include the mouth in the plan view seen in the X-axis direction. The mouth opens in the Y-axis direction in this embodiment, which is orthogonal to the X-axis direction.