This paper reports that the time-domain accuracy of bare-hand interactions in HMD-based Augmented Reality can be improved by using finger contact: touching a finger with another or tapping one's own hand. The activation of input can be precisely defined by the moment of finger contact, allowing the user to perform the input precisely at the desired moment. Finger contact is better suited to the user's mental model, and natural tactile feedback from the fingertip also benefits the user with the self-perception of the input. The experimental results revealed that using finger contact is the preferred method of input that increases the time-domain accuracy and enables the user to be aware of the moment the input is activated.