The clinical manifestations of OSA (obstructive sleep apnea) are night sleep snoring accompanied by apnea. fNIRS (functional near-infrared spectroscopy) can measure the relative concentration changes of oxyhemoglobin and deoxyhemoglobin, thereby measuring hemodynamics and oxygenation. Combined with the clinical manifestations of obstructive sleep apnea, fNIRS technology can be used in the monitoring of OSA. According to the principle of fNIRS, a miniaturized, wireless, and flexible device is designed in the article. The device can measure the change of blood oxygen concentration in the forehead of the brain, so that achieve the purpose of detecting OSA. To verify the effectiveness of the equipment, a breathing experiment was designed in the article to compare the equipment with the existing NIRX system.