A tube connection structure (1) according to the present invention is configured from a first connector (2) and a second connector (3) which are fitted to each other. The first connector (2) is provided with: an outer cylinder (22) a communication part (23) in which, in a fitted state, a fluid passage (23c) enabling a fluid to circulate is formed and an annular valve body (24) which is provided to a periphery of the communication part (23), and which, in a non-fitted state, seals an outer-cylinder opening (22a). The second connector (3) is provided with: an inner cylinder (32) which, in a fitted state, pushes in the annular valve body (24) an inside valve body which, in a non-fitted state, seals an inner-cylinder opening (32a), and which, in a fitted state, is pushed in by the communication part entering inside the inner cylinder (32) via the inner-cylinder opening (32a) and a first seal member (41) which is provided to at least an inner peripheral surface of the inner-cylinder opening (32a), and which, in a fitted state, fluid-tightly seals a space between the inner-cylinder opening (32a) and the communication part (23) inserted into the inner-cylinder opening (32a). This tube connection structure (1) is characterized in that the fluid passage (23c) is provided in a communication-part (23) section which, in a fitted state, enters inside the inner cylinder (32).La structure daccouplement pour tube (1) de linvention est configurée par un premier ainsi quun second connecteur (2, 3) ajustés entre eux. Le premier connecteur (2) est équipé : dun tube externe (22) dune partie communication (23) dans laquelle est formé un trajet de liquide (23c) permettant lécoulement dun liquide en mode ajustement et dun corps de valve circulaire (24) agencé à la périphérie de la partie communication (23) qui enferme hermétiquement une partie ouverture de tube externe (22a) en mode non ajustement. Le second connecteur (3) est équipé : dun tube interne (32) poussant le corps de valve cir
