To provide a caster fixing structure which allows a caster to be securely attached and fixed to the body of a bag such as a traveler's bag, a suitcase, or a carry bag so that the bag can be moved quietly without causing noise and vibration during a travel.

The caster fixing structure includes a caster 10 which is attached and fixed to the body 1 of a bag by fixtures (screws 20) made of rigid material via a cushioning material 32, wherein the caster and fixtures are attached and fixed without being directly brought into contact with the body 1 of the bag.