Provided is an optical scanning observation apparatus including: a light source unit (30) for outputting laser light; a scanning part (23) for scanning, on an object of observation (70), a condensing position of the laser light output from the light source; and a detection unit (40) for sampling signal light obtained through scanning of the laser light, and converting the signal light into an electric signal, in which a sampling time for detecting signal light per one sampling is varied in accordance with changes in scanning rate of the scanning part (24) scanning on the object of observation (70). In this manner, variation in resolution of an image resulting from changes in scanning rate per each sampling can be reduced.