A boron nitride fine particle has low major diameter/thickness (aspect) ratio, high purity and high crystallinity, and also has an average particle diameter of 0.05 to 2.0 μm, a graphitization index of 3 or less, and a total oxygen content of 0.20% by mass or less, with an average value of a major diameter/thickness ratio of scaly particles being 6.0 or less. A method of producing a boron nitride fine particle includes introducing ammonia and an alkoxide borate at an ammonia/alkoxide borate molar ratio of 1 to 5 in a reaction vessel in an inert gas atmosphere for heating at 800 to 1,350° C. within 30 seconds thereby obtaining a boron nitride precursor, and then heating the boron nitride precursor at 1,650 to 2,200° C. for at least 0.5 hour in an inert gas atmosphere.