Abstract: An ultrasonic flow meter of the present invention includes: a measurement flow path 6 through which a fluid to be measured flows; ultrasonic transducers 8 and 9 provided respectively on an upstream side and a downstream side with respect to each other along the measurement flow path 6; an upstream aperture hole 11 and a downstream aperture hole 12, the aperture holes 11 and 12 for exposing the ultrasonic transducers 8 and 9 to the measurement flow path 6; a first influent suppressor 15 provided in a vicinity of at least the downstream aperture hole 12 for reducing inflow of the fluid to be measured into the aperture hole 12; a second influent suppressor 16 provided on an upstream side of the measurement flow path 6 with respect to the aperture holes 11 and 12 for reducing the inflow of the fluid to be measured into the aperture holes 11 and 12; a measurement control section 19 for measuring a propagation time of an ultrasonic wave between the ultrasonic transducers 8 and 9; and a calculation section 20 for ca