Disclosed herein are an infrared (IR) sensor and a sensing method using the same, in which disturbance by an external luminous object is removed using the IR sensor that irradiates IR light into a sensing area to sense an object, so that the position or distance of the object can be precisely and accurately sensed. An IR sensor includes an illumination unit that irradiates IR light into a sensing area; an image pickup device that obtains an IR image in the sensing area by sensing the IR light incident from the sensing area; and a control unit that controls the emission time at which the illumination unit irradiates the IR light and the pickup time of the image pickup device. In the IR sensor, the control unit includes an illumination controller that controls the emission time of the illumination unit; an image pickup device controller that controls the pickup time of the image pickup device; a memory that stores the IR image obtained by the image pickup device; and an image processor that calculates the position or distance of the object in the sensing area by performing comparison operation processing with respect to an IR image obtained when the illumination unit irradiates the IR light and an IR image obtained when the illumination unit does not irradiate the IR light in the IR images stored in the memory.