A mask apparatus comprising: a mask body; a fan module (16, 17) configured to be coupled to the mask body; a seal that is coupled to a rear surface of the mask body and defines a breathing space therein; a pressure sensor coupled to the mask body and configured to sense an air pressure in the breathing space; a mask body cover coupled to a front surface of the mask body and configured to cover the fan module (16, 17); and a controller coupled to the mask body and configured to control a rotation speed of the fan module (16, 17) based on the air pressure sensed by the pressure sensor, wherein the controller is configured to: extract maximum pressure values and minimum pressure values among a plurality of air pressure values sensed by the pressure sensor; extract maximum time points corresponding to the maximum pressure values and minimum time points corresponding to the minimum pressure values; determine breathing cycles, each cycle being defined by a period of time between two time points at which two adjacent maximum air pressure values are sensed or at which two adjacent minimum air pressure values are sensed; determine an expected time point of inhalation in a next breathing cycle; and increase the rotation speed of the fan module (16, 17) when the expected time point of the inhalation of the next breathing cycle arrives, wherein the controller is configured to calculate the expected time point of inhalation in a subsequent breathing cycle based on information of a current breathing cycle, wherein the controller is configured to determine a time point, at which a time corresponding to about 20% to about 50% of the current time difference elapses from a time point at which the maximum pressure value is sensed in the next breathing cycle, as the expected time point of the inhalation. a mask body; a fan module (16, 17) configured to be coupled to the mask body; a seal that is coupled to a rear surface of the mask body and defines a breathing space therein; a pressure sensor coupled to the mask body and configured to sense an air pressure in the breathing space; a mask body cover coupled to a front surface of the mask body and configured to cover the fan module (16, 17); and a controller coupled to the mask body and configured to control a rotation speed of the fan module (16, 17) based on the air pressure sensed by the pressure sensor, wherein the controller is configured to: extract maximum pressure values and minimum pressure values among a plurality of air pressure values sensed by the pressure sensor; extract maximum time points corresponding to the maximum pressure values and minimum time points corresponding to the minimum pressure values; extract maximum pressure values and minimum pressure values among a plurality of air pressure values sensed by the pressure sensor; extract maximum time points corresponding to the maximum pressure values and minimum time points corresponding to the minimum pressure values; determine breathing cycles, each cycle being defined by a period of time between two time points at which two adjacent maximum air pressure values are sensed or at which two adjacent minimum air pressure values are sensed; determine an expected time point of inhalation in a next breathing cycle; and increase the rotation speed of the fan module (16, 17) when the expected time point of the inhalation of the next breathing cycle arrives, wherein the controller is configured to calculate the expected time point of inhalation in a subsequent breathing cycle based on information of a current breathing cycle, wherein the controller is configured to determine a time point, at which a time corresponding to about 20% to about 50% of the current time difference elapses from a time point at which the maximum pressure value is sensed in the next breathing cycle, as the expected time point of the inhalation. determine an expected time point of inhalation in a next breathing cycle; and increase the rotation speed of the fan module (16, 17) when the expected time point of the inhalation of the next breathing cycle arrives, wherein the controller is configured to calculate the expected time point of inhalation in a subsequent breathing cycle based on information of a current breathing cycle, wherein the controller is configured to determine a time point, at which a time corresponding to about 20% to about 50% of the current time difference elapses from a time point at which the maximum pressure value is sensed in the next breathing cycle, as the expected time point of the inhalation.