The present invention relates to a smartphone-based hearing aid which does not employ a separate power supply or digital signal processing device and instead has an analogue interface unit, configured with a single integrated circuit chip, connected between a plurality of microphones and a smartphone, thereby realizing a compact size, reducing the cost and enhancing the audio performance. Instead of employing a digital signal processing chip which is essentially used in the existing hearing aids or personal sound amplifiers, the smartphone-based hearing aid according to the present invention utilizes components such as a smartphone-embedded application processor (AP), RAM, digital-analogue converter, speaker and display and is therefore affordable. In particular, if a CPU and a GPU which are embedded in the application processor of the smartphone are utilized, digital signal processing necessary for the operation of the hearing aid can be performed within a short time of milliseconds (ms) just by using software.