The object of the present invention is to provide a device for detecting with higher sensitivity emission light in the form of fluorescence or phosphorescence emitted from a micro-object irradiated by an excitation light. The present invention provides means for suppressing reflected and scattered light arising from excitation light impinging on the semiconductor detection element of the device, comprising a pinhole formed in a fluorescence collecting microlens, through which the excitation light passes, irradiating the micro-object. The device may also be provided with another means for suppressing reflected and scattered excitation light comprising a non-horizontal surface that is not perpendicular to the excitation light, formed on a part of the light-transparent chip surface from which the excitation light exits.