A plasma spectroscopy analysis method comprising: a preparatory process of diluting a urine sample assumed to contain mercury or lead as an analyte metal species, wherein, in the preparatory process, in a case in which an endogenous creatinine concentration in the urine sample exceeds 180 mg/dL, the urine sample is diluted such that the creatinine concentration is from 75 mg/dL to 180 mg/dL, and then adding a known concentration of thallium as a control metal species to the diluted urine sample; a concentration process of introducing the urine sample containing the control metal species 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 present in the urine 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 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 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 E2=(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 urine 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 diluting a urine sample assumed to contain mercury or lead as an analyte metal species, wherein, in the preparatory process, in a case in which an endogenous creatinine concentration in the urine sample exceeds 180 mg/dL, the urine sample is diluted such that the creatinine concentration is from 75 mg/dL to 180 mg/dL, and then adding a known concentration of thallium as a control metal species to the diluted urine sample; a concentration process of introducing the urine sample containing the control metal species 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 present in the urine 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 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 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 E2=(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 urine sample by comparing the corrected value to a calibration curve obtained by advance measurements of known concentrations of the analyte metal species.