Provided are an apparatus and method for estimating a breathing rate using a microphone, which performs band filtering and noise filtering on tracheal and nasal sounds collected from the microphone, selects a processing region of preprocessed data, calculates similarity between pieces of data using an autocorrelation function, calculates a power spectrum density, detects multiple peaks including a highest peak through the power spectrum density, analyzes the multiple peaks to determine a breathing pattern, and calculates a breathing rate in consideration of a dynamic characteristic between inhalation and exhalation, nasal congestion detection, and noise reduction. Accordingly, it is possible to accurately estimate the breathing rate because calculation is performed in consideration of a dynamic characteristic of inhalation and exhalation, nasal congestion, and white noise.