PURPOSE: To make possible separation and recombination of combined upper and lower halves and to assemble the cartridge case in simple work.

CONSTITUTION: One pair of halves 31 and 32 are combined by fitting engagement protruding parts 33 and 34 to each other, formed on their opposite inner surfaces, and a 1st combiner 40 provided with a restraining flange part 43 and a restraining projected line 44 on both sides of a cylindrical base part 41 having a fitting hole 42 is fitted into a fitting hole 35 provided on an engagement protruding part 33 of one half 31. By this method, both halves 31 and 32 are combined in a temporarily fixing state by holding the fitted engagement protruding parts 33 and 34 between the restraining flange part 43 and the restraining projected line 44, and a fitting shaft part 46 of a 2nd combiner 45 is press-fitted into the fitting hole 42 of the 1st combiner 40 to combine the two halves 31 and 32.