Abstract: An apparatus for measuring a fluid microflow velocity within a capillary conduit, comprises: a) at least one thermoelectric cooler having a heating and a cooling surface, said heating surface being suitable for heating a fluid flowing over it and said cooling surface being suitable for cooling said fluid; and b) a capillary conduit through which said fluid flows, said capillary conduit passing through said at least one thermoelectric cooler in heat-exchanging positioned relationship with its heating and cooling surfaces.