Previous studies of second language acquisition show that the "input" plays a key role for successful second language learning. However, language teachers tend to focus on the output rather than the input given to the learners. The present study examine the effects of input-based instruction called the Processing Instruction on two types of linguistic features in Japanese, and compare whether the effectiveness of the instruction differ between syntactic and lexical features. The target items chosen for this study were the causative construction and irregular humble expressions, both of which are considered difficult features for second language learners to acquire. Thirty beginninglevel learners were divided into two groups, and the each group received an instruction on one of the target items. The participants of this study were given comprehension and production tests on three different occasions: before, immediately after, and one week after the instruction. The results indicated that the learners in both groups gained from the instruction and retained the gain after one week. Also, while they did equally well on the production tests, this was not the case for the comprehension tests, that is, the instructional gain was greater than causative construction for the humble expressions. It suggests the effectiveness of the Processing Instruction differs by linguistic features.