Release force reduction is necessary for reliable UV nanoimprint. The effect of inclined mold detachment and pentafluoropropane as an ambient gas was investigated using a UV-nanoimprint stepper with a mold orientation control and a gas introduction system. The inclined release was realized by diverting the mold orientation control for directing a mold parallel to a wafer commonly used after mold exchange. A pentafluoropropane environment was generated in UV-nanoimprinting space by a gas introduction system within a UV-nanoimprint stepper. The inclined release showed a reduction in release force in comparison to parallel release at this experiment. However, the inclined release is only modestly beneficial for release force reduction. In contrast, the ambient gas in which UV nanoimprint is carried out has a significant impact on release force. Release force can be reduced to one-third of what is obtained in air by using pentafluoropropane. It is quite beneficial to use pentafluoropropane not only for bubble elimination but also for the reduction in release force.