The invention relates to a method for separating a target for measurement utilizing electrophoresis, particularly capillary electrophoresis efficiently in high sensitivity and in a short period of time. It also relates to a method for measuring said target separated by said method for separation. The invention provides a method for separating a target for measurement and a method for measuring said target separated by said method for separation, characterized by using a substance to which is bound a nucleic acid chain labeled by a marker and which has an affinity for said target for measurement.