To easily observe a transparent object to be observed such as a biological cell.

The observation apparatus includes: an image acquiring part which includes an image-forming optical system for forming an image of light emitted from an object to be observed that is an observation object; an imaging means for picking up images formed by the image-forming optical system, and a lighting means comprising a bright part extending in a main scanning direction of the object to be observed and a dark part holding the bright part in a subscanning direction orthogonal to the main scanning direction, where the bright part is arranged to be deviated in the subscanning direction relative to an optical axis of the image-forming optical system; and a moving mechanism which moves the image acquiring part or the object to be observed in the subscanning direction and changing a relative position of the image acquiring part to the object to be observed. It is desirable to arrange the bright part of the lighting means to be deviated relative to the optical axis of the image-forming optical system by an interval obtained from an effective aperture on an incident side of the image-forming optical system, a distance from the image-forming optical system to the object to be observed and a distance from the lighting means to the object to be observed in the subscanning direction.