A tube connection assembly comprises a male member, a female member and a mating member. The male member is provided with a retaining part that is formed with a non-circular cross-section on the outer peripheral part of a male body. The mating member is held by the retaining part, is formed from an elastic material having a C-shape, and has, on a portion thereof, mating parts. The female member is provided with a receiving part in which the male member is inserted, and mating holes and formed through the receiving part. The mating member is held, so as to prevent rotation, by a base part of a retaining part that has a non-circular cross-section as a part of the outer peripheral part of the male body, and decreases or increases in diameter in the radial direction to mate with the female member through insertion into the mating holes.