A novel multi-beam circular dichroism (CD) detector for HPLC is described. A unique feature of this detector is the use of a retardation plate to give many quarter-waves in the wavelength region of interest. When a polarizing prism and a thin quartz plate as the retarder are placed in a conventional photodiode array (PDA) detector, the kinetic spectra of an optically active analyte recorded by the instrument contain sinusoidal CD waves in the wavelength axial direction. Extraction of these CD waves superimposed on the absorption spectra was performed with MS Excel. Both the instrumental conditions for the PDA data acquisition and the polynomial data processing were optimized by monitoring the chromatographic elution of camphor. The limit of detection for ajimaline, a chiral alkaloid, was 26 ng injected amount.