An unmanned aerial vehicle, comprising: a main body; a plurality of frames (102, 211) extending from the main body; and a plurality of thrust generating devices (104, 200, 400, 500, 600) respectively mounted on the plurality of frames, each of the thrust generating devices including a propeller, wherein the propeller includes: a hub that provides a rotation axis of the propeller, and is adapted to rotate according to an operation of the thrust generating device, a pair of blades (227, 327, 427, 527), each of which is pivotably mounted on the hub, and are adapted to generate a thrust or lift while rotating around the rotation axis as the hub is rotated, and a pair of gears (229, 329), each of the gears being provided at end of one of the blades and rotatably mounted on the hub as being engaged with each other and are adapted to interlock the blades with each other, and wherein the blades are interlocked with each other such that the blades are adapted to be aligned to a folded position in which the blades are parallel with each other on the hub in a first arrangement or aligned to an expanded position in a diametric direction of a rotating region of the propeller in a second arrangement, and characterized in that the propeller further includes: a rotation hole that is formed to penetrate opposite surfaces of each of the gears along a rotation axis direction; a mounting hole that extends in a direction perpendicular to the rotation axis from a side surface of each of the gears; and a fixing hole formed in each of the blades, and wherein an end of each of the blades is inserted into, and mounted in, the mounting hole while the fixing hole is aligned to the rotation hole. a main body; a plurality of frames (102, 211) extending from the main body; and a plurality of thrust generating devices (104, 200, 400, 500, 600) respectively mounted on the plurality of frames, each of the thrust generating devices including a propeller, wherein the propeller includes: a hub that provides a rotation axis of the propeller, and is adapted to rotate according to an operation of the thrust generating device, a pair of blades (227, 327, 427, 527), each of which is pivotably mounted on the hub, and are adapted to generate a thrust or lift while rotating around the rotation axis as the hub is rotated, and a pair of gears (229, 329), each of the gears being provided at end of one of the blades and rotatably mounted on the hub as being engaged with each other and are adapted to interlock the blades with each other, and a hub that provides a rotation axis of the propeller, and is adapted to rotate according to an operation of the thrust generating device, a pair of blades (227, 327, 427, 527), each of which is pivotably mounted on the hub, and are adapted to generate a thrust or lift while rotating around the rotation axis as the hub is rotated, and a pair of gears (229, 329), each of the gears being provided at end of one of the blades and rotatably mounted on the hub as being engaged with each other and are adapted to interlock the blades with each other, and wherein the blades are interlocked with each other such that the blades are adapted to be aligned to a folded position in which the blades are parallel with each other on the hub in a first arrangement or aligned to an expanded position in a diametric direction of a rotating region of the propeller in a second arrangement, and characterized in that the propeller further includes: a rotation hole that is formed to penetrate opposite surfaces of each of the gears along a rotation axis direction; a mounting hole that extends in a direction perpendicular to the rotation axis from a side surface of each of the gears; and a fixing hole formed in each of the blades, and a rotation hole that is formed to penetrate opposite surfaces of each of the gears along a rotation axis direction; a mounting hole that extends in a direction perpendicular to the rotation axis from a side surface of each of the gears; and a fixing hole formed in each of the blades, and wherein an end of each of the blades is inserted into, and mounted in, the mounting hole while the fixing hole is aligned to the rotation hole.