The present invention relates to a filtration method, a filter-incorporated tip and a filtration device, and its object is to perform efficient and swift isolation of a target substance. The filtration method therefore comprises: a liquid introducing step to introduce a liquid into a filter-incorporated tip through a guide opening portion thereof, wherein the filter-incorporated tip has a nozzle-tipped container and a filter, the nozzle-tipped container has a guide opening portion that can be directly or indirectly fitted to an air nozzle capable of ejecting a gas and a front nozzle portion capable of delivering the liquid by the ejection of the gas from the air nozzle, and the filter is locked in the nozzle-tipped container to partition the interior of the nozzle-tipped container into the guide opening portion side and the front nozzle portion side and is adapted to temporarily hold the liquid and isolate a predetermined substance as the liquid passes through the filter, with the nozzle-tipped container coupled to the air nozzle on the guide opening portion side; a coupling step to directly or indirectly couple the filter-incorporated tip containing the liquid to the air nozzle; and a pressure application step to eject the gas from the air nozzle into the coupled filter-incorporated tip.