A microfluidic device and a method for separating target cells by using same are provided. A microfluidic device according to an embodiment of the present invention is for separating, from a biological sample, a first material in the sample, and comprises: a body that is rotatable around a rotary shaft; a mixing chamber which is provided in the body, and in which the sample and a magnetic bead, to be coupled with a second material in the sample, are mixed; a separation chamber which is provided in the body, which is connected to the mixing chamber, and in which a mixed sample, having the second material that is coupled with the magnetic bead and the first material mixed therein, is separated; and a magnetic member disposed on one side of the outside of the separation chamber, wherein the microfluidic device can be formed so that, in the separation chamber, the second material, coupled with the magnetic bead and the first material are separated by means of centrifugal force and magnetic force.
