In a fluid metering device for metering a fluid from a supply source to means of use of this fluid comprising a metering valve able to slide in a sleeve over a travel C, this valve comprising an intake orifice (16) for admitting the fluid from the said supply source and an orifice (18) for ejecting this fluid to the means of use, there are provided means (20) for channelling the fluid intended to allow, during the movement of the metering valve in its sleeve, a sweeping of the fluid over all the contacting surfaces of the valve and of the sleeve. The means of channelling the fluid advantageously comprise a helical groove of width L and of pitch P.