To provide a configuration for enhancing the working efficiency when mounting a measurement unit with a cable and when replacing parts with new ones in a flowmeter of the type for fixing the measurement unit to a meter body using a fixed ring.

A fixing ring 8 for fixing a measurement unit 7 of the flowmeter 1 is made of an elastically deformable resin material. A cable insertion hole 82 is formed at a protruding part 8i that is formed into one piece at the fixing ring 8. A first joint part 81 that reaches a ring lower surface part 8h and a second seam part 8e that reaches a side surface part 8j of the protruding part 8i are formed from the cable insertion hole 82. By expanding the seam parts 81 and I3 when covering the measurement unit 7 with the fixed ring 8, a signal cable 73 can be passed easily to the cable insertion hole 82 through the first joint part 81.