An insertion apparatus includes: a tube in which a water feeding communication hole opens on an outer peripheral surface of the tube; a tube connector in which a water feeding branch conduit which allows an inner surface of a tube insertion hole to communicate with an outside is formed, and a second stopper portion which protrudes toward the inside of the tube insertion hole is formed; an O ring which is positioned by contacting with the second stopper portion; a spacer which is positioned by contacting with the O ring, and in which a communication hole which allows an inner surface side and an outer surface side of a wall portion to communicate with each other is formed; and an O ring which is positioned by contacting with the spacer.