Our previous study found that children with developmental dyslexia used mainly non-lexical processing rather than lexical processing due to inefficient lexical processing during Kana word naming, and their non-lexical processing itself was also slow. The aim of this study was to confirm whether adults with developmental dyslexia also show the same problems, that is, inefficient lexical processing and slow non-lexical processing. To accomplish this aim, we ran a reading aloud experiment investigating effects of length and lexicality on reading latencies for strings of Kana characters. Participants were 7 adults with developmental dyslexia and 48 normal adults. The dyslexic group showed longer reading latencies than the normal group and a significantly large length effect irrespective of lexicality, findings that are compatible with results in our previous study. Therefore it is thought that the adults with developmental dyslexia in this study had the same problems in both lexical and non-lexical processing as the children with developmental dyslexia had in our previous study.