Rec巳nL1 } ・ , the mic1 齟 oHuidic device sucb as F TAS has bceエ 1 attra, cted ill many 且elds . Since surface for ' ces become dominant with Clecreasing of a Iength scalc . it isdiMcult to remove thebubbleattached to the charlnel in a device . All unoxpected adhesion of a bubble causes the large pressure l〔〕ss (} r deterioration of the device . We have suggested the n 〔 mc 〔mtact bubble rr]anipulation method using photQthenma ]八 ' [ arang 〔 mi e 匠 fect .、Vhen the nuid in the vicinity of the

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... is irra 〔 1iated by し hc laser and local temperature gradient is { nduced around tlle bubble, Marangoni convection alung thc gas − liquid i飢 crface { 〕 ccurs due lo the su [ 『 face tension gradie 【 ユt. As a rcsult , ヒ he bubble migrates to the laser sPot and scanning of the laser spot enables transportation of the bubble, In this paper , the rnigration behavior of the bubble along thc channel was invesしigated. W ビ also ol)tained t} 1ern 量 nimum optical p ( , wer for the manipulation with diffeTent conditions 〔 レ f bubble sizes , scanning speed alld kinematic viscosity of liquid . Experimental results can be summarized by a 〔 liinensionless nur 丁] ber which meaDs a ratio of thermocapillary forcc to viscous drag force 、 Universa[criteria on migration are indica し cd by the dimensionless nurnber .