We experimentally examined the effect of observation and motivation on human motor learning. In this study, an arm reaching movement under a viscous curl force field was adopted as learning task. The subjects in Observation group were asked to just look at an expert's movement before starting the learning session. In addition, the subjects in Motivation group were provided with the information that they have to tackle the same task after the observation. Experimental results demonstrated that the subjects with the observation outperformed the subjects without observation (i.e. control group). Moreover, the subjects with the motivated observation showed rapid performance improvement compared with those of not-motivated observation. These results suggest that attentive observation have a positive effect on the early stage of human motor learning.