PURPOSE: To improve productivity, by a method wherein the ear part of a connecting rod body and the ear part of a cap for internal combustion engine and a mating face are previously finish-machined, and a coupling hole part, simultaneously, is machined in a condition in that the rod body and the cap are abutted on each other by the use of a jig.

CONSTITUTION: A rod body 1 and a cap 2 have ear parts 1a and 2a, respectively, coupling holes 3, positioned on the same line, are formed in the ear part 1a of the rod body 1 and the ear part 2a of the cap 2, and the rod body 1 and the cap 2 are intercoupled by means of a tightening bolt 4, inserted into the coupling hole 3, in a condition in that mating faces 1b and 2b of the two ear parts 1a and 2a are abutted on each other. The coupling hole 3 is formed with a coupling hole part 3a which is a half part located closer to the mating faces 1b and 2b and engaging with the tightening bolt 4 without leaving a gap, an escape hole part 3b being a half on the outer end side, and seat surfaces 3c. In which case, the mating faces 1b and 2b are finish-machined and secured to a jig in a condition in that the rod body 1 and the cap 2 are abutted on each other and the coupling hole part 3a of the coupling hole 3, simultaneously, is machined in a range of the two ear parts 1b and 2b.