A remarkable reduction of the L-H threshold power was observed in JT-60Uunderthe W-shaped pumped divertor geometry, in comparison with the resultsfor theprevious open divertor. The density range was extended to 0.6nGWL( = Ip/πa2), wherea stronger than linear density dependence was found. A reduction of theradiationpower and edge temperature as well as a nonlinear increase in edge densitywere also observed. The poloidal distribution of the neutral particle densitywas first examined in this work, and it was found that compression of neutralparticles near the X-point or loss of homogeneity on a flux surface producedby the modification of the divertor geometry may be an influential determinantof the L-H threshold power.