Abstract: Previous studies on sound symbolism of Japanese onomatopoeia have reported that the phonological feature [±voice] of a word-onset consonant causes contrastive meanings/impressions. However, whether or not [±voice] of word-internal consonants, as well as other phonological features, produces different meanings/impressions has remained unclear. Using semantic differential and factor analysis on Japanese onomatopoeic words, we examined the effects of word-internal consonants, as well as of word-onset consonants, on sound symbolism. We replicated previous findings, showing that the phonological feature [±voice] of the word-onset consonants caused sound symbolism related to psychological state (e.g. tense/relaxed), movement (e.g. heavy/light), shape (e.g. large/small), and sound (e.g. noisy/quiet). We also found for the first time that [±voice] of the word-internal consonants made contrastive meanings/impressions related to movement, shape, and sound. Furthermore, [±sonorant] of both word-onset and word-internal consonants caused sound symbolism of the onomatopoeia related to psychological state and sound. Our results demonstrate that the phonological features of [±voice] and [±sonorant], which produce contrastive meanings/impressions, are crucial for sound symbolism in onomatopoeia.