1. An image acquisition device, comprising: a stage on which a sample is placed; a light source configured to emit instantaneous light; a light guiding optical system including an objective lens arranged to face the sample on the stage; an imaging sensor configured to capture an optical image of the sample guided by the light guiding optical system; a driver configured to move a position of a field of view of the objective lens relative to the sample at a predetermined velocity; and a controller configured to control the light source, wherein the imaging sensor is a two-dimensional imaging sensor including a plurality of pixel rows and for sequentially capturing at a predetermined frame rate, and the velocity is a velocity set based on at least the frame rate.