An ultrasound sensor comprising: a transmitter outputting a plurality of first ultrasound beams having different frequencies and a plurality of second ultrasound beams having different frequencies; a receiver receiving a first reflection signal among a plurality of reflection signals, which are reflected from an object in response to the output plurality of first ultrasound beams; and a controller determining a first area in a space, controlling the transmitter to respectively output the plurality of first ultrasound beams to a plurality of first sub-areas that are included in the first area, and determining whether the object is included in each of the plurality of first sub-areas, based on the first reflection signal, wherein the receiver receives a plurality of second reflection signals, which are reflected from the object in response to the plurality of second ultrasound beams, and the controller controls the transmitter to respectively output the plurality of second ultrasound beams to a plurality of third sub-areas that are included in the plurality of first sub-areas, and determines whether the object is included in each of the plurality of third sub-areas, based on the plurality of second reflection signals, wherein the highest frequency from among frequencies of the plurality of first ultrasound beams is lower than the highest frequency from among frequencies of the plurality of second ultrasound beams, wherein the transmitter comprises a plurality of output elements and a first output element from among the plurality of output elements outputs an ultrasound beam for determining the first area, the receiver receives a reflection signal for determining the first area, which is reflected from the object in response to the ultrasound beam for determining the first area, and the controller obtains a first point of the object that is the closest to the first output element, based on the reflection signal for determining the first area, and determines the first area that includes the first point. a transmitter outputting a plurality of first ultrasound beams having different frequencies and a plurality of second ultrasound beams having different frequencies; a receiver receiving a first reflection signal among a plurality of reflection signals, which are reflected from an object in response to the output plurality of first ultrasound beams; and a controller determining a first area in a space, controlling the transmitter to respectively output the plurality of first ultrasound beams to a plurality of first sub-areas that are included in the first area, and determining whether the object is included in each of the plurality of first sub-areas, based on the first reflection signal, determining a first area in a space, controlling the transmitter to respectively output the plurality of first ultrasound beams to a plurality of first sub-areas that are included in the first area, and determining whether the object is included in each of the plurality of first sub-areas, based on the first reflection signal, wherein the receiver receives a plurality of second reflection signals, which are reflected from the object in response to the plurality of second ultrasound beams, and the controller controls the transmitter to respectively output the plurality of second ultrasound beams to a plurality of third sub-areas that are included in the plurality of first sub-areas, and determines whether the object is included in each of the plurality of third sub-areas, based on the plurality of second reflection signals, controls the transmitter to respectively output the plurality of second ultrasound beams to a plurality of third sub-areas that are included in the plurality of first sub-areas, and determines whether the object is included in each of the plurality of third sub-areas, based on the plurality of second reflection signals, wherein the highest frequency from among frequencies of the plurality of first ultrasound beams is lower than the highest frequency from among frequencies of the plurality of second ultrasound beams, wherein the transmitter comprises a plurality of output elements and a first output element from among the plurality of output elements outputs an ultrasound beam for determining the first area, the receiver receives a reflection signal for determining the first area, which is reflected from the object in response to the ultrasound beam for determining the first area, and the controller obtains a first point of the object that is the closest to the first output element, based on the reflection signal for determining the first area, and determines the first area that includes the first point. obtains a first point of the object that is the closest to the first output element, based on the reflection signal for determining the first area, and determines the first area that includes the first point.