To provide a copper alloy cast billet with which the productivity is further improved by reducing a tool wearing in tube making while holding the processing facility in the production of a copper alloy tube and the productivity; and the copper alloy tube produced by processing the copper alloy cast billet.

In the cast billet for producing the copper alloy tube with a hot-extrusion; the cast billet has the composition composed by mass% of 0.004-0.05% P, 0.01-1.0% Zn and the balance Cu with inevitable impurities. To this copper alloy cast billet, hot-extrusion processing, rolling processing, extractive-drawing processing and annealing processing, are applied to produce the copper alloy tube.