A plasma spectroscopy analysis method comprising: a preparatory process of adding a control metal species that is different from an analyte metal species to a sample so as to have a known concentration, wherein the control metal species is at least one metal species selected from the group consisting of zinc, cadmium, silver, gold, thallium, and indium, and the analyte metal species is either mercury or lead; a concentration process of introducing the sample to a measurement container, and applying an electric current across a pair of electrodes (20, 30) disposed in the measurement container to concentrate the analyte metal species and the control metal species in the sample in a vicinity of at least one of the electrodes (20, 30); a detection process of applying an electric current across the pair of electrodes (20, 30) after the concentration process so as to generate plasma, and detecting emitted light from the analyte metal species and the control metal species arising due to the plasma; a correction process of calculating a corrected value by dividing an analysis emission amount E 1 at an analysis wavelength corresponding to the analyte metal species detected in the detection process, by a control emission amount E 2 at a control wavelength corresponding to the control metal species detected in the detection process; wherein the analysis emission amount E 1 is related to a peak emission amount P 1 at the analysis wavelength and a base emission amount B 1 at the analysis wavelength, and wherein the control emission amount E 2 is related to a peak emission amount P 2 at the control wavelength and a base emission amount B 2 at the control wavelength, such that: E 1 = P 1 − B 1 / B 1; and E 2 =(P 2 -B 2)/B 2; or E 1 = P 1 − B 1 and E 2 =(P 2 -B 2); or E 1 = P 1 / B 1 and E 2 =P 2 /B 2 and a quantification process of quantifying the analyte metal species in the sample by comparing the corrected value to a calibration curve obtained by advance measurements of known concentrations of the analyte metal species. a preparatory process of adding a control metal species that is different from an analyte metal species to a sample so as to have a known concentration, wherein the control metal species is at least one metal species selected from the group consisting of zinc, cadmium, silver, gold, thallium, and indium, and the analyte metal species is either mercury or lead; a concentration process of introducing the sample to a measurement container, and applying an electric current across a pair of electrodes (20, 30) disposed in the measurement container to concentrate the analyte metal species and the control metal species in the sample in a vicinity of at least one of the electrodes (20, 30); a detection process of applying an electric current across the pair of electrodes (20, 30) after the concentration process so as to generate plasma, and detecting emitted light from the analyte metal species and the control metal species arising due to the plasma; a correction process of calculating a corrected value by dividing an analysis emission amount E 1 at an analysis wavelength corresponding to the analyte metal species detected in the detection process, by a control emission amount E 2 at a control wavelength corresponding to the control metal species detected in the detection process; wherein the analysis emission amount E 1 is related to a peak emission amount P 1 at the analysis wavelength and a base emission amount B 1 at the analysis wavelength, and wherein the control emission amount E 2 is related to a peak emission amount P 2 at the control wavelength and a base emission amount B 2 at the control wavelength, such that: E 1 = P 1 − B 1 / B 1; and E 2 =(P 2 -B 2)/B 2; or E 1 = P 1 − B 1 and E 2 =(P 2 -B 2); or E 1 = P 1 / B 1 and E 2 =P 2 /B 2 and a quantification process of quantifying the analyte metal species in the sample by comparing the corrected value to a calibration curve obtained by advance measurements of known concentrations of the analyte metal species.