HEAT TRANSFER TUBE WITH INNER SURFACE GROOVE, HEAT EXCHANGER INCLUDING HEAT TRANSFER TUBE WITH INNER SURFACE GROOVE, AND METHOD OF MANUFACTURING THE SAME

PROBLEM TO BE SOLVED: To provide a heat transfer tube with inner surface grooves aiming at a reduction in tube diameter and improvement of heat transfer performance, and a heat exchanger including the same.SOLUTION: In a heat transfer tube 10 with inner surface grooves, which has fins 12 in the inner surface of a heat transfer tube 11 and inserted into a through-hole 32 formed in a plurality of plate-like stacked fins 31 to penetrate therethrough and is also attached after its diameter is increased, an outer diameter Dof the heat transfer tube 11 is not less than 2.8 mm and not more than 5.0 mm, a helix angle of each of the fins 12 is not less than 0 degrees and not more than 8 degrees, a height Hfof the fin before its diameter is increased is not less than 0.16 mm and not more than 0.25 mm, and a number N of lines of each of the fins 12 is 40 or less.