An ICP emission spectrometer is schematically configured to include an inductively coupled plasma generation unit, a light condensing unit, a spectroscope, a two-dimensional detection unit and a controller. The two-dimensional detection unit includes a CCD image sensor which has multiple pixels laid in a planar shape and detects emission light by causing the emission light emitted from the spectroscope to be imaged on the multiple pixels. Then, the controller determines a pixel used in detecting the emission light among the multiple pixels in accordance with an imaging shape of detection-targeted emission light.