To provide a gas cooler equipped with a dust collection function capable of effectively cooling high, temperature gas produced from an incinerator, etc.

A gas cooling chamber 14 filled with cooling water in an outer tank 13 is provided. A plurality of fine tubes 16 are passed in the gas cooling chamber 14 to permit high temperature gas to pass through the insides of the fine pipes. Further, there is provided a cylindrical pre-cooling chamber 23 communicated with a lower portion of the gas cooling chamber 14 through a communication pipe 22. The pre-cooling chamber 23 is constructed with a double structure wall 25 including a jacket 26 for containing cooling water, and an air supply port 33 is provided in the pre-cooling chamber 23 for introducing the high temperature gas. The high temperature gas introduced into the pre-cooling chamber 23 from the air supply port 33 flows into the interior of the fine pipe 16 through the communication pipe 22 while turning along an internal surface of the pre-cooling chamber 23. Soot and dust in the high temperature gas are separated and removed from the high temperature gas with centrifugal force upon the turning. The high temperature gas after cooled in the pre-cooling chamber 23 is re-cooled in the gas cooling chamber 14. For this, the high temperature gas is effectively cooled, and cooling efficiency of the gas cooling chamber 14 is not lowered because soot and dust are unlikely to be deposited in the fine pipe 16.