A heat transfer tube with passages formed inside, the heat transfer tube comprising: a tube body made of an extruded material of an aluminum alloy having a composition consisting of: 0.3 mass% or more and less than 0.8 mass% of Mn; more than 0.1 mass% and less than 0.32 mass% of Si; 0.3 mass% or less of Fe; 0.06 mass% or more and 0.3 mass% or less of Ti; 0.05 mass% or less of Cu; less than 0.05 mass% of Mg; and less than 0.03 mass% of Cr; and Al balance including inevitable impurities, a ratio of a Mn content to a Si content, Mn%/Si%, exceeding 2.5; and a Zn-containing layer provided to an outer surface of the tube body, wherein a thickness of a wall part sectioning the passages has a thin structure of 0.1-1.5 mm; the heat transfer tube has an extrusion weld part, which is a weld line generated by merging of two flows of softened metal in a mold when molding is performed by putting metal softened by being heated into the mold, by being formed by extruding work; selective corrosion at the extrusion weld part is suppressed; the aluminum alloy constituting the tube body is an alloy subjected to a homogenization treatment in which an ingot of the aluminum alloy after casting is kept at 450-650oC for 2-24 hours; a heating rate from a room temperature to 450oC is 50-180oC/h; a heating rate from 450oC to a temperature of the homogenization treatment is 10-80oC/h; and a cooling rate from the temperature of the homogenization treatment to 200oC is 50-400oC/h, in the homogenization treatment; 3000/mm 2 or less of intermetallic compound precipitates whose size is 1.0 μm or more in a circle equivalent diameter are precipitated in the heat transfer tube after a brazing heat treatment or a Zn diffusing treatment of the heat transfer tube, and a brazing heat treatment or a Zn diffusing treatment is performed on the heat transfer tube at 610oC or lower. a tube body made of an extruded material of an aluminum alloy having a composition consisting of: 0.3 mass% or more and less than 0.8 mass% of Mn; more than 0.1 mass% and less than 0.32 mass% of Si; 0.3 mass% or less of Fe; 0.06 mass% or more and 0.3 mass% or less of Ti; 0.05 mass% or less of Cu; less than 0.05 mass% of Mg; and less than 0.03 mass% of Cr; and Al balance including inevitable impurities, a ratio of a Mn content to a Si content, Mn%/Si%, exceeding 2.5; and a Zn-containing layer provided to an outer surface of the tube body, wherein a thickness of a wall part sectioning the passages has a thin structure of 0.1-1.5 mm; the heat transfer tube has an extrusion weld part, which is a weld line generated by merging of two flows of softened metal in a mold when molding is performed by putting metal softened by being heated into the mold, by being formed by extruding work; selective corrosion at the extrusion weld part is suppressed; the aluminum alloy constituting the tube body is an alloy subjected to a homogenization treatment in which an ingot of the aluminum alloy after casting is kept at 450-650oC for 2-24 hours; a heating rate from a room temperature to 450oC is 50-180oC/h; a heating rate from 450oC to a temperature of the homogenization treatment is 10-80oC/h; and a cooling rate from the temperature of the homogenization treatment to 200oC is 50-400oC/h, in the homogenization treatment; 3000/mm 2 or less of intermetallic compound precipitates whose size is 1.0 μm or more in a circle equivalent diameter are precipitated in the heat transfer tube after a brazing heat treatment or a Zn diffusing treatment of the heat transfer tube, and a brazing heat treatment or a Zn diffusing treatment is performed on the heat transfer tube at 610oC or lower. a thickness of a wall part sectioning the passages has a thin structure of 0.1-1.5 mm; the heat transfer tube has an extrusion weld part, which is a weld line generated by merging of two flows of softened metal in a mold when molding is performed by putting metal softened by being heated into the mold, by being formed by extruding work; selective corrosion at the extrusion weld part is suppressed; the aluminum alloy constituting the tube body is an alloy subjected to a homogenization treatment in which an ingot of the aluminum alloy after casting is kept at 450-650oC for 2-24 hours; a heating rate from a room temperature to 450oC is 50-180oC/h; a heating rate from 450oC to a temperature of the homogenization treatment is 10-80oC/h; and a cooling rate from the temperature of the homogenization treatment to 200oC is 50-400oC/h, in the homogenization treatment; 3000/mm 2 or less of intermetallic compound precipitates whose size is 1.0 μm or more in a circle equivalent diameter are precipitated in the heat transfer tube after a brazing heat treatment or a Zn diffusing treatment of the heat transfer tube, and a brazing heat treatment or a Zn diffusing treatment is performed on the heat transfer tube at 610oC or lower.