Provided is a fluid measuring device for measuring flow speed of a fluid in detail. A fluid measuring device (10) is provided with a plurality of detecting sections (30, 40) and a calculating section (50). The detecting sections are arranged with a space in between on a pipe line (22) wherein a fluid flows, and the detecting sections detect parameters which change corresponding to a change of the state of the fluid. The calculating section calculates the flow speed of the fluid, based on the time shift (Delta T) of the parameter change detected by the pair of detecting sections and on a distance (L) along the pipe line of the pair of detecting sections.