To provide a method for measuring the flow velocity and flow rate of a fluid flowing in piping without any contact from the outside of the piping.

In the method for measuring flow velocity without any contact using electromagnetic ultrasonic waves, an electromagnetic ultrasonic wave transmitter 2 is arranged closely without any contact on the outer-periphery surface of piping 6 where fluid 8 is circulated, ultrasonic waves are generated in the piping or fluid by the electromagnetic ultrasonic wave transmitter 2, the fluid and piping are vibrated by ultrasonic energy being propagated in the fluid, an ultrasonic detector 4 is arranged without any contact outside the vibrating piping, magnetic field is given into the piping or fluid from the ultrasonic transmitter and at the same time the magnetic field is allowed to be fluctuated due to the vibration of the ultrasonic waves, the fluctuating magnetic field is detected by the ultrasonic detector 4 for detecting an ultrasonic wave arrival point P, flow velocity (u) of the fluid is measured from an interval ΔL between a stand still point O when the fluid is still and a fluid arrival point when the fluid is flowing, and ultrasonic wave propagation time τ is obtained through u=ΔL/τ. With the configuration, the flow velocity and flow rate of the fluid can be measured without any contact from the outside of the piping. Also, they can be accurately measured without being affected by the temperature of the fluid and the vibration of the piping since the measurement is made without any contact.