Provided are a fluid conveying tube and a fluid leakage detecting system which can convey a cryogenic fluid such as LNG and which can quickly and reliably detect leakage of the fluid within the tube and the position of the leakage. An optical fiber is continuously wound over the entire length of a flexible tube. Leakage information detected by an optical fiber temperature sensor is transmitted via a terminal to an externally provided temperature measurement device. Meanwhile, when similar leakage occurs in the vicinity of a coupling section, the gas pressure inside the heat insulating layer or the like increases due to the pressure of LNG within a corrugated tube or a pressure generated as a result of evaporation of LNG. When the pressure inside the heat insulating layer increases, information representing a change in the gas pressure is transmitted to a terminal via a hollow pipe. A tube or the like is externally connected to the terminal, and is connected to a pressure meter or like.