Copper alloy tube for heat exchanger

The copper alloy tube of the present invention has a composition containing Sn: 0.1 to 2.0% by mass, P: 0.005 to 0.1% by mass, S: 0.005% by mass or less, O: 0.005% by mass or less, and H: 0.0002% by mass or less, and the balance It consists of Cu and unavoidable impurities. Further, in the annealed state, the tensile strength is 250 N/mm 2 or more, and the average crystal grain diameter measured in a direction perpendicular to the wall thickness direction of the tube in the orthogonal cross section of the tube axis is 30 μm or less. The tensile strength of the copper alloy tube in the longitudinal direction is σL, and when the tensile strength in the circumferential direction is σT, σT/σL>0.93. According to such a configuration, it is possible to increase the tensile strength as much as possible without deteriorating the bending workability, and it is possible to sufficiently improve the withstand voltage breaking strength (breaking pressure), and also excellent in bending workability and heat resistance.