This study tried to establish both critical and desirable levels of health-related physical fitness (HRPF) including muscle strength (relative grip strength), flexibility and estimated VO₂max. Subjects were 3102 males aged 20 to 59 years. Four batteries of health index score (HIS-A-D) were made based on health examinations and lifestyle habits. Subjects who had 0 to 1 points were defined as healthy individuals, and subjects who had more than 3 or 4 points were defined as unhealthy. Receiver-operating characteristic (ROC) curves were drawn by HRPF test in each battery of HIS. The HIS-B was selected as the most valid battery of HIS. Sensitivity, specificity and the Youden index were calculated using cut-off values which were mean values of each HRPF test measurement in each group who had 0, 1, 2, 3 and>4 points in HIS-B. The critical levels were defined the highest specificity and/or Youden index in each HRPF test. There were seen in groups having > 4 points. The desirable levels were defined as the HRPF test levels in healthy individuals who had 0 to 1 points in HIS-B. The critical and desirable levels of VO₂max were 41.8 and 50.2 at 20y, 40.9 and 46.2 at 30y, 40.0 and 46.2 at 40y, and 37.8 and 45.5 ml/kg/min at 50y, respectively. The levels of other HRPF test were also calculated in the present study. Exercise guidance after health check-ups should be done to attain desirable levels rather than to just maintain critical levels of HRPF.