To provide an electrode cleaning apparatus and an ion concentration measuring apparatus each of which is made compact and has a simple structure.

The surface 4b of an electrode 4 is cleaned by oscillating a cleaning oscillator 11 with a vortex generated by a vortex generator 10 and rubbing the oscillator 11 on the surface 4b. The oscillator 11 is a columnar member consisting of polypropylene whose density is smaller than that of water, for example. The surface 11a of the oscillator 11 faced to the surface 4b is brought into contact with the surface 4b by making the oscillator 11 float by the buoyancy given from a fluid flowing in a flow passage 2c. In the concrete, the oscillator 11 is oscillated in the arrow direction since the force of the generated and spouted Karman vortex and the buoyancy act on the oscillator 11 alternately in the direction perpendicular to the flow direction of the fluid. As a result, since the oscillator 11 is oscillated in the arrow direction in such a state that the surface 4b is in contact with the surface 11a and the surface 4b is rubbed by the surface 11a, the surface 11a can be cleaned and the fur or the like stuck to the surface 4b can be removed.