This paper proposes a readout integrated circuit (ROIC) for $32{ imes}32$ infrared focal plane array (IRFPA) detector, which consist of reference resistor, detector resistor, reset switch, integrated capacitor and operational amplifier. Proposed ROIC is designed using $0.35{;}{mu}m$ 2P-4M (double poly four metal) n-well CMOS process parameters. Low noise folded cascode operational amplifier which is a key element in the ROIC showed 12.8 MHz unity-gain bandwidth and open-gain 89 dB, phase margin $67^{circ}$, SNR 82 dB. From proposed circuit, we gained output voltage variation ${Delta}17{};mV/^{circ}C$ when the detector resistor varied according to the temperature.