A hose coupling assembly wherein a hose 20 having a corrugated portion 22 is coupled to a fitting block 24 by a socket 50. The fitting block 24 has a block engagement catch 25c projecting from the outside rim of the block body 25. The socket 50 comprises a socket body 51 elastically expandable and contractible by being divided by a slit 51a, and a socket engagement catch 51b engages the block engagement catch 25c. To detach the socket 50 from the fitting block 24, force is applied in a rotation direction to a push operation portion 51c to cause the socket body 51 to undergo diametrical expansion, releasing the socket engagement catch 51b from the block engagement catch 25c.