A humidifier with regular addition of fixed quantity of essential oil is located in public areas and configured such that humidified air contains fragrance regularly. The humidifier is provided with a main body, water storage bucket mounted to the main body, and essential oil supplier mounted to the main body. The essential oil supplier includes a casing, at least one essential oil bottle within the casing and stored with essential oil, at least one peristaltic pump corresponding to each bottle and connected to the main body to be controlled. Each peristaltic pump is controlled by the main body, such that fixed quantity of essential oil is supplied regularly by the humidifier with the water storage bucket being not dismounted to keep fragrance in atomizing air continuous and eliminate the problem of only presence of fragrance at the beginning of addition of essential oil due to conventional method of addition.
