The critical heat fluxes were measured for the one-side insulated flat plates for bulk liquid temperatures from saturated ones down to 2.0 K at pressures of 101 and 130 kPa. The test plates were made or Manganin. 10 mm in width and 40 mm in length and 0.1 mm in thickness. Effect of inclination of the test plate was systematically studied from the horizontal one facing upward (theta = 0) to that facing downward (theta = pi). The critical heat flux gradually becomes lower with the increase in theta up to around pi /2 and the decreasing rate becomes especially higher for the 0 larger than pi /2. The critical heat flux increases with the decrease of bulk liquid temperature and the effect of inclination disappears from lambda temperature. A correlation for critical heat flux in He I including the effects of subcooling and the inclination was given based on the experimental data. The experimental data are described by the equation within 15 % difference.