A Voice Coil Motor comprising: a base unit ; a bobbin having a rotation prevention unit ; a coil disposed on the bobbin , a yoke comprising an upper plate , a lateral plate extending from the upper plate and an inner unit extending from the upper plate , a magnet oppositely disposed to the coil; and an upper elastic member disposed on an upper surface of the bobbin , wherein the inner unit of the yoke is configured to be hitched by the rotation prevention unit to prevent rotation of the bobbin , wherein a first gap is formed between a lateral surface of the rotation prevention unit and a lateral surface of the inner unit of the yoke facing the lateral surface of the rotation prevention unit , the magnet comprises four magnets disposed on four corners of the yoke , respectively, the rotation prevention unit comprises a plurality of rotation prevention units , and wherein the inner unit of the yoke comprises a plurality of inner units , characterized in that a recess portion is formed in a shape of a staircase having a first depth from an upper surface of the rotation prevention unit , and a second depth formed from the lateral surface of the rotation prevention unit , a second gap is formed between a lateral surface of the recess portion and the lateral surface of the inner unit of the yoke , the second gap is greater than the first gap, the recess portion is configured to reduce a contact area between the rotation prevention unit and the inner unit of the yoke by the first depth of the recess portion , and the bobbin is protrusively formed at a periphery with the plurality of rotation prevention units along the periphery of the bobbin , where four rotation prevention units are formed along the periphery of the bobbin , each spaced apart at a predetermined distance. a base unit ; a bobbin having a rotation prevention unit ; a coil disposed on the bobbin , a yoke comprising an upper plate , a lateral plate extending from the upper plate and an inner unit extending from the upper plate , a magnet oppositely disposed to the coil; and an upper elastic member disposed on an upper surface of the bobbin , wherein the inner unit of the yoke is configured to be hitched by the rotation prevention unit to prevent rotation of the bobbin , wherein a first gap is formed between a lateral surface of the rotation prevention unit and a lateral surface of the inner unit of the yoke facing the lateral surface of the rotation prevention unit , the magnet comprises four magnets disposed on four corners of the yoke , respectively, the rotation prevention unit comprises a plurality of rotation prevention units , and wherein the inner unit of the yoke comprises a plurality of inner units , characterized in that a recess portion is formed in a shape of a staircase having a first depth from an upper surface of the rotation prevention unit , and a second depth formed from the lateral surface of the rotation prevention unit , a second gap is formed between a lateral surface of the recess portion and the lateral surface of the inner unit of the yoke , the second gap is greater than the first gap, the recess portion is configured to reduce a contact area between the rotation prevention unit and the inner unit of the yoke by the first depth of the recess portion , and the bobbin is protrusively formed at a periphery with the plurality of rotation prevention units along the periphery of the bobbin , where four rotation prevention units are formed along the periphery of the bobbin , each spaced apart at a predetermined distance. <EOS>