The basic functions of the nose are the humidifying and warming of inspired air, filtering of air-born particles, and olfaction. Airflow patterns in the nasal cavity affect the performance of these functions. Velocity fields of human nasal cavity were investigated using DPIV (Digital Particle Image Velocimetry) in the present paper. A three times scaled-up half-nasal model of a human nasal cavity was constructed for the investigation of nasal flow patterns. To overcome the difficulties concerning DPIV for the study of flow patterns within the human nasal cavity in the air flow with physiological conditions, liquid was used instead of air. In this study tetrahydronaphtalene was chosen as a carrier medium in order to match the refractive index of working fluid to that of the solid transparent model for DPIV measurements. Steady flow rate equivalent to still breathing through one side of the real human nasal cavity was investigated here.