A component analysis method comprising: a measurement process in which a sample solution that is continuously introduced into a flow path is separated into a plurality of components inside the flow path and is optically measured over time at a measurement position on the flow path to obtain optical measurement values, wherein the optical measurement values are optical absorbance values or transmitted light intensity values; and an analysis process in which the plurality of components contained in a sample (Sa) is analyzed based on the optical measurement values, the analysis process including: a base waveform acquisition process in which a base waveform is acquired by associating each optical measurement value with a time point at which each optical measurement value is acquired, such that the optical measurement values are capable of being plotted as a function of time along a time axis on a two-dimensional plane; a measurement value differentiation process in which a measurement value differentiated waveform is acquired, which is a waveform obtained by differentiating the base waveform to first order with respect to optical measurement value along an axis of the optical measurement values orthogonal to the time axis; and a measurement value boundary determination process in which the optical measurement values corresponding to peaks in the measurement value differentiated waveform are determined to be separation boundaries between adjacent components of the plurality of components. a measurement process in which a sample solution that is continuously introduced into a flow path is separated into a plurality of components inside the flow path and is optically measured over time at a measurement position on the flow path to obtain optical measurement values, wherein the optical measurement values are optical absorbance values or transmitted light intensity values; and an analysis process in which the plurality of components contained in a sample (Sa) is analyzed based on the optical measurement values, the analysis process including: a base waveform acquisition process in which a base waveform is acquired by associating each optical measurement value with a time point at which each optical measurement value is acquired, such that the optical measurement values are capable of being plotted as a function of time along a time axis on a two-dimensional plane; a measurement value differentiation process in which a measurement value differentiated waveform is acquired, which is a waveform obtained by differentiating the base waveform to first order with respect to optical measurement value along an axis of the optical measurement values orthogonal to the time axis; and a measurement value boundary determination process in which the optical measurement values corresponding to peaks in the measurement value differentiated waveform are determined to be separation boundaries between adjacent components of the plurality of components. a base waveform acquisition process in which a base waveform is acquired by associating each optical measurement value with a time point at which each optical measurement value is acquired, such that the optical measurement values are capable of being plotted as a function of time along a time axis on a two-dimensional plane; a measurement value differentiation process in which a measurement value differentiated waveform is acquired, which is a waveform obtained by differentiating the base waveform to first order with respect to optical measurement value along an axis of the optical measurement values orthogonal to the time axis; and a measurement value boundary determination process in which the optical measurement values corresponding to peaks in the measurement value differentiated waveform are determined to be separation boundaries between adjacent components of the plurality of components.