A fitting confirmation construction includes a confirmation part in a first connector and a confirmation opening in a second connector. A rib is provided in the confirmation opening. A height of the confirmation part is equal to a height of the rib and the confirmation part and the rib are positioned on a same line, on a viewing direction which is viewed from an obliquely upper position rearward in an inserting direction of the second connector through the confirmation opening, in a state that the second connector is completely fit with the first connector.