A solid phase extraction method with a micro device having a dam-forming portion including a dam , wherein each of the dam-forming portion and the dam has a circular cross section with respect to a central axis of the micro device , the method comprising the steps of: (i) injecting a solvent and a filler into the micro device to move to the dam-forming portion , wherein the filler is filled in the form of a disk with respect to the central axis in the dam-forming portion , the dam being adjusted to allow only the solvent to flow through but the filler not to pass through and, thereby adsorbing a material to be separated onto the filler in the dam-forming portion ; and (ii) extracting the adsorbed material to be separated from the filler , wherein in one step of the steps (i) and (ii), the micro device is rotated about the central axis of the micro device , and the rotation of the micro device is performed at an angular velocity defined by Equation 1 below. ω > g r cos 90 ° − φ wherein, ω is a rotational angular velocity of the micro device in units of s -1 , g is an acceleration of gravity in units of m s -2 , r is a radius of the dam-forming portion or a radius of the dam of the micro device in units of m, φ is an angle at which the central axis of the micro device is inclined from an axis of a horizontal plane, and φ is in the range of 0° <φ <90°. (i) injecting a solvent and a filler into the micro device to move to the dam-forming portion , wherein the filler is filled in the form of a disk with respect to the central axis in the dam-forming portion , the dam being adjusted to allow only the solvent to flow through but the filler not to pass through and, thereby adsorbing a material to be separated onto the filler in the dam-forming portion ; and (ii) extracting the adsorbed material to be separated from the filler , wherein in one step of the steps (i) and (ii), the micro device is rotated about the central axis of the micro device , and the rotation of the micro device is performed at an angular velocity defined by Equation 1 below. ω > g r cos 90 ° − φ wherein, ω is a rotational angular velocity of the micro device in units of s -1 , g is an acceleration of gravity in units of m s -2 , r is a radius of the dam-forming portion or a radius of the dam of the micro device in units of m, φ is an angle at which the central axis of the micro device is inclined from an axis of a horizontal plane, and φ is in the range of 0° <φ <90°. wherein in one step of the steps (i) and (ii), the micro device is rotated about the central axis of the micro device , and the rotation of the micro device is performed at an angular velocity defined by Equation 1 below. ω > g r cos 90 ° − φ wherein, ω is a rotational angular velocity of the micro device in units of s -1 , g is an acceleration of gravity in units of m s -2 , r is a radius of the dam-forming portion or a radius of the dam of the micro device in units of m, φ is an angle at which the central axis of the micro device is inclined from an axis of a horizontal plane, and φ is in the range of 0° <φ <90°. ω is a rotational angular velocity of the micro device in units of s -1 , g is an acceleration of gravity in units of m s -2 , r is a radius of the dam-forming portion or a radius of the dam of the micro device in units of m, φ is an angle at which the central axis of the micro device is inclined from an axis of a horizontal plane, and φ is in the range of 0° <φ <90°. <EOS>