A metering valve for dispensing fluid, having a valve body containing a metering chamber, and a valve member slidable axially in the valve body between rest position and dispensing positions, the valve member urged towards its rest position by a spring. The valve member including a central axial channel provided with an axial outlet orifice and with a radial inlet channel arranged in the metering chamber when the valve member is in its dispensing position. The radial inlet channel including an inlet opening and an outlet opening that opens out into the central axial channel, the diameter of the radial inlet channel in the range 0.30 mm to 0.40 mm. The diameter of the outlet opening is equal to the diameter of the radial inlet channel, and the diameter of the inlet opening is greater than the diameter of the radial inlet channel.