Abstract: In a fluid periodic pressure wave motion attenuating hose in which an inner tube thereof serving as a main conduit portion is coaxially mounted in the hose so as to form an annular space portion between an inner peripheral surface of the hose and an outer peripheral surface of the inner tube, which annular space portion serves as a side-branch portion and is partially communicated with the above main conduit portion of the hose at a predetermined position, the opposite end portions of the inner tube are fixed to a pair of couplings connected with opposite fluid ducts so as to positively define the above side-branch portion against the main conduit portion of the hose and so as to surely support the inner tube. In addition, the inner tube may be constructed of a wire-like spring member and a strip-like metallic member both coiled together to axially alternate in parallel to each other in a close-contact manner, while relaxed in its close-contact at the above predetermined position.