There is provided a rolling bearing used in a liquefied gas environment or in an extremely low temperature, wherein an inner ring and an outer ring are made of steel material which is any one of bearing steel, stainless steel, high-speed tool steel and cemented steel, and a rolling element of the rolling bearing is made of ceramic having a coefficient of linear expansion of 70% to 105% of a coefficient of linear expansion of the steel material forming the inner ring and outer ring. A liquefied gas pump including the rolling bearing is also provided. Further, there is provided a cage which contains PTFE, a fibrous reinforcing material and a solid lubricant, and which is suitable for the above rolling bearing or the like.