FLOWMETER

PROBLEM TO BE SOLVED: To prevent the action of fluid pressure in the radial direction imbalanced to an impeller caused by a sensor housing part housing a magnetic detecting element protruded into a fluid flow passage in a magnetic detection type flow meter having an axial flow type impeller. SOLUTION: A projection part 8 in which a detection element 23 of a magnetic sensor 22 is housed is projected into a fluid passage 3 of a water meter 1. A flow straightener main body part 73 of a flow straightener 7 arranged in the position upstream than an impeller 6 is installed in a position displayed by the specified amount in the opposite direction to the projection side of the projection part 8 to a passage center shaft line 3a. Large amount of water is guided toward the projection side of the projection part 8 by the flow straightener. Unequal water pressure in the radial direction acting to the impeller 6 caused by the projection part 8 can be suppressed or reduced. As a result, drop in durability in a bearing part of the impeller can be prevented.