A HART analog input module with a differential input comprises a plurality of input stage processors respectively connected to a plurality of HART field devices to detect a DC signal and a HART communication signal from an input signal and output the DC signal and a HART communication signal, in a case a signal superimposed with the DC signal and the HART communication signal is inputted from a relevant HART field device, a multiplexer sequentially outputting a DC signal and a HART communication signal respectively outputted from each input stage processor in response to a provided control signal, an A/D conversion processor converting a DC signal of each channel sequentially outputted from the multiplexer to a digital signal, a HART modem demodulating a HART communication signal of each channel sequentially outputted from the multiplexer, and a controller providing a control signal to the multiplexer and processing the digital signal outputted from the A/D conversion processor and the HART modem.