Cubic boron nitride sintered material and method of producing same

A cubic boron nitride sintered material comprising:

• more than or equal to 20 volume % and less than 80 volume % of cubic boron nitride grains;
• and more than 20 volume % and less than or equal to 80 volume % of a binder phase, wherein
• the binder phase includes at least one selected from a group consisting of a compound composed of at least one element selected from a group consisting of a group 4 element, a group 5 element, a group 6 element in a periodic table, and aluminum, and at least one element selected from a group consisting of nitrogen, carbon, boron, and oxygen, and a solid solution originated from the compound, and
• when a carbon content is measured from a cubic boron nitride grain into the binder phase in a direction perpendicular to an interface between the cubic boron nitride grain and the binder phase using TEM-EDX, a first region having a carbon content larger than an average value of a carbon content of the binder phase exists, the interface exists in the first region, and a length of the first region is more than or equal to 0.1 nm and less than or equal to 10 nm.