The particle diffusivity and the convection velocity in the reversed shear plasma of JT-60U were separately evaluated based on the perturbation technique using modulated helium gas-puffing. The particle diffusivity in the region of internal transport barrier was reduced by about a factor of two compared with that in the inside region. The inward convection velocity was observed in the region of internal transport barrier, while the outward convection velocity was observed in the inside region. These results indicate that the changes in both the particle diffusivity and the convection velocity are related to the formation of the internal transport barrier.