A system for detecting microbes is provided. In the system for detecting microbes, light is emitted to a sample through a light emission module, a sensor module detects speckles generated when the emitted light is scattered by motion of bacteria or microbes contained in the sample, and a controller stores and analyzes images detected by the sensor module to test microbial detection, wherein controller may include a light emission controller connected to the light emission module and configured to control an emission period and an emission intensity of light emitted by the light emission module; an imaging collector connected to the sensor module and configured to store a speckle image generated through multiple scattering by the bacteria or microbes contained in the sample; a corrector configured to correct a deviation caused by a difference in the amount of light when the light emission module emits the light; and an estimator configured to estimate, in real-time, presence or absences of the bacteria or microbes in the sample or a concentration of the bacteria or microbes.