The present technology provides a beam forming device for performing both analog beam forming and analog-to-digital conversion. The present invention provides a probe having a beam forming device therein, and a system comprising the same. A beam forming device, according to the present technology, comprises: a signal storage circuit configured to receive the plurality of analog signals to store the analog beam signal corresponding to a combination of the plurality of analog signals; and a control circuit configured to control the signal storage circuit so that the signal storage circuit receives the plurality of analog signals and stores the analog beam signal, to generate a digital signal corresponding to the analog beam signal and to control the signal storage circuit so that an output voltage of the signal storage circuit is updated while the digital signal is being generated.