A brushless direct current (BLDC) motor comprising: a stator; and a rotor disposed inside of the stator, wherein the rotor is formed of a metal in a cylindrical shape in which an outer circumferential surface thereof corresponds to an inner circumferential surface of the stator, the rotor including a plurality of permanent magnet parts, each of the permanent magnet parts including first and second permanent magnets (111, 112) which are disposed to have an interval therebetween, wherein the rotor includes a slot part including a first portion into which the first permanent magnet is inserted, a second portion into which the second permanent magnet is inserted, and a third portion connecting the first and second portions (121, 122) to each other, the third portion being an empty space penetrating the rotor; and wherein the first and second portions (121, 122) have one end portions which are spaced apart from each other by a first distance and other end portions which are spaced apart from each other by a second distance which is shorter than the first distance, and the third portion connects the other end portions of the first and second portions (121, 122) to each other, wherein the first and second permanent magnets (111, 112) have thicknesses which increase from the other end portion adjacent to an inner circumferential surface of the rotor to the one end portion that is disposed to be spaced apart from the outer circumferential surface of the rotor by a predetermined interval, wherein one end portions (111a, 112a) of the first and second permanent magnets (111, 112) have the same curvature as an inner circumferential surface of the stator, and wherein the third portion includes: a first surface connecting points (121a, 122a) corresponding to each other of the respective other end portions of the first and second portions (121, 122); and a second surface connecting other points (121b, 122b) corresponding to each other of the respective other end portions of the first and second portions (121, 122), the second surface including three surfaces in three different planes,. a stator; and a rotor disposed inside of the stator, wherein the rotor is formed of a metal in a cylindrical shape in which an outer circumferential surface thereof corresponds to an inner circumferential surface of the stator, the rotor including a plurality of permanent magnet parts, each of the permanent magnet parts including first and second permanent magnets (111, 112) which are disposed to have an interval therebetween, wherein the rotor includes a slot part including a first portion into which the first permanent magnet is inserted, a second portion into which the second permanent magnet is inserted, and a third portion connecting the first and second portions (121, 122) to each other, the third portion being an empty space penetrating the rotor; and wherein the first and second portions (121, 122) have one end portions which are spaced apart from each other by a first distance and other end portions which are spaced apart from each other by a second distance which is shorter than the first distance, and the third portion connects the other end portions of the first and second portions (121, 122) to each other, wherein the first and second permanent magnets (111, 112) have thicknesses which increase from the other end portion adjacent to an inner circumferential surface of the rotor to the one end portion that is disposed to be spaced apart from the outer circumferential surface of the rotor by a predetermined interval, wherein one end portions (111a, 112a) of the first and second permanent magnets (111, 112) have the same curvature as an inner circumferential surface of the stator, and wherein the third portion includes: a first surface connecting points (121a, 122a) corresponding to each other of the respective other end portions of the first and second portions (121, 122); and a second surface connecting other points (121b, 122b) corresponding to each other of the respective other end portions of the first and second portions (121, 122), the second surface including three surfaces in three different planes,. a first surface connecting points (121a, 122a) corresponding to each other of the respective other end portions of the first and second portions (121, 122); and a second surface connecting other points (121b, 122b) corresponding to each other of the respective other end portions of the first and second portions (121, 122), the second surface including three surfaces in three different planes,.