The　motion　of　the　Taylor　bubbles　in　vertical　and　near-vertical　tubes　was　investigated.　The　non-invasive　measurements　were　conducted　by　using　a　high-speed　motion　analyzer.　For　the　vertical　slug　flow,　the　coefficient　C1　was　found　to　be　very　close　to　the　ratio　of　the　maximum　velocity　to　the　average　velocity　in　the　profile.　For　the　inclined　slug　flow,　the　value　of　C1　is　smaller　than　that　for　the　vertical　case　because　the　nose　tip　of　the　Taylor　bubble　usually　deviates　from　the　centerline.　The　drift　velocity　is　increased　with　the　decrease　of　inclination　angle.　Based　on　the　theoretical　analysis　and　experimental　data,　the　bubble　velocity　correlations　were　obtained.　The　results　are　in　good　agreement　with　the　data　available.