The objective of this research is to evaluate the infection risk by the aerosol dispersion due to human cough in a medical examination room. The experiments were conducted in a full-scale test room simulated as a medical examination room. Two types of manikins were employed. One was a "Coughing Manikin," which could simulate human cough airflow using carbon dioxide (CO2) as a tracer gas. The other was a "Thermal Manikin," which was used as a medical doctor. Eleven conditions were examined by varying the manikin positions, airflow patterns using a push-pull ventilation system (PPVS), and other conditions. For the evaluation of the infection risk, both CO2 concentration and the capture efficiency of CO2 were used. It was concluded that the PPVS influenced the decrease in the infection risk depending on the CO2 concentration and the capture efficiency. Further, it was revealed that the PPVS arrangement was an important concern.