A device and method for detecting cerebral microbleeds use magnetic resonance images. The disclosed device includes a preprocessing unit that normalizes an SWI image and a phase image, respectively, of the magnetic resonance images, and performs phase image conversion for inverting a code of the normalized phase image, a YOLO neural network module that receives a two-channel image in which the preprocessed SWI image and phase image are concatenated and detects a plurality of candidate regions for the cerebral microbleeds, and a cerebral microbleeds determination neural network module that receives patch images of candidate regions of the SWI image and phase image based on the candidate regions and determines whether the patch images of each candidate region are an image with a symptom of the cerebral microbleeds through a neural network operation.