Local　resistances　caused　by　abrupt　expansion　and　contraction　were　experimentally　investigated　for　the　small　channels　with　diameters　from　0.330　mm　to　0.580　mm　by　using　a　novel　pressure　measurement　method　of　the　tiny　gaps　on　the　channels.　The　experimental　results　showed　that　the　pressure　measurement　method　through　the　gaps　was　a　feasible　method　for　small　channels.　For　laminar　flow,　the　expansion　loss　coefficient　was　much　lower　and　the　contraction　loss　coefficient　was　much　higher　as　compared　with　the　experimental　results　of　conventional　channels,　while　for　turbulent　flow,　the　expansion　and　contraction　loss　coefficients　were　consistent　with　those　of　the　conventional　channels.