To provide a part coupling structure by which separated parts to be coupled can be surely and easily fixed and the coupled parts can be easily disassembled.

In a part coupling structure 10 in which two parts 1A, 1B to be coupled are joined at least at one joint portion 1c, the parts 1A, 1B to be coupled includes through holes 1Ad, 1Bd respectively formed at least at one portion penetrating astride the joint portion 1c, a hollow cylindrical member 2 of a cylindrical shape inserted into the through holes 1Ad, 1Bd astride the joint portion 1c, and plug members 3A, 3B of which outer circumferential portions 3Aa, 3Bb contact with an inner circumferential portion 2b of the cylindrical member 2. At least one of the inner circumferential portion 2b of the cylindrical member 2 and the outer circumferential portions 3Aa, 3Bb of the plug members 3A, 3B has a tapered shape. The minimum diameter of the inner circumferential portion 2b of the cylindrical member 2 is smaller than the maximum diameter of the outer circumferential portions 3Aa, 3Bb of the plug members 3A, 3B. The plug members 3A, 3B are arranged in a central axis direction of the cylindrical member 2.