A software analyzing device capable of extracting a candidate for an unauthorized feature or an unnecessary feature contained in a code of software is to be provided. The software analyzing device includes a feature identifying means for identifying a predetermined specific feature in a code of software, a control-flow identifying means for identifying a control flow connecting with the specific feature, and a candidate extracting means for extracting, as a candidate for an unauthorized feature or an unnecessary feature, a first code part the code of the software unreachable from the control flow connecting with the specific feature.