Data of mooring observation in Kitanada Bay, located on the eastern coast of Bungo Channel in Japan, obtained during summer 2001 are analyzed to investigate a modification process of the semidiurnal internal tide by density currents, occasionally occurring in the channel. The mooring data show that the semidiurnal internal tide has the character of low vertical mode standing wave. When the bottom slope near the mooring station is near-critical, the energy of the semidiurnal internal tide in the lower layer reached the maximum value. Since the density current modifies the density stratification occasionally creating the near-critical condition, it strongly affects the intensity of the semidiurnal internal tide energy in the lower layer.