A gas hydrate production apparatus capable of reacting a raw gas with a raw water to thereby form a slurry gas hydrate and capable of removing water from the slurry gas hydrate by means of a gravitational dewatering unit. This gravitational dewatering unit is one including a cylindrical first tower body; a cylindrical dewatering part disposed on top of the first tower body; a water receiving part disposed outside the dewatering part; and a cylindrical second tower body disposed on top of the dewatering part, wherein the cross-sectional area of the second tower body is continuously or intermittently increased upward from the bottom.