The present invention provides a solid phase extraction method using a micro device having a dam forming portion including a dam, the solid phase extraction method comprising the steps of: (i) injecting a solvent and a filler into the micro device, moving the solvent to the dam forming portion, the dam allowing the solvent to flow therethrough and preventing the filler from passing therethrough, and adsorbing a material to be separated onto the filler in the dam forming portion; and (ii) extracting, from the filler, the adsorbed material, wherein the micro device is rotated with respect to a central axis during one of steps (i) and (ii), and the rotation of the micro device is performed at an angular velocity defined by equation 1.