In this paper, the effects of three lexical properties in processing Japanese are investigated using an eye-movement monitoring technique. The lexical properties investigated in this paper are: 1) familiarity of lexical items; 2) acceptability of orthography; and 3) transparency of sound-character correspondence in orthography. The stimuli sentences were all simple Japanese sentences with four to five phrases, in canonical word order as well as scrambled word order. In accord with previous studies that reported significant effects on reaction times, etc., of these lexical properties when tested in isolation, our results showed that all three lexical properties showed significant effects on eye movement. In particular, lexical familiarity showed a strong effect on all measured aspects of sentence processing. The effect of orthography was significant, not in terms of whether words were written in Kanji or in Kana , but on how appropriate the orthography was for the particular word. In addition, the degree of transparency between orthography and pronunciation had a limited but significant effect on the gaze duration. This implies that phonological processing may influence silent reading. The effect of scrambled word order was observed in the total gaze duration and it was mainly caused by increasing frequency of regressive eye-movement.