With rapid spread of acceptance and usage of Social Network Service (SNS, e.g., Facebook, Renren, Myspace), concerns about online information privacy have arisen. This paper explores the instruments of users' privacy concerns in the context of SNS. First, based on the relevant literature review, comparisons among four scales are discussed and necessities of new items are proposed. Then a pilot test with an open question is carried out collecting 28 samples through interviews. Several reliable and specific new items are added through qualitative content coding. And this is followed by an integrated questionnaire survey. Analyses of 115 respondents' data indicate that SNS user's concerns about privacy are covering a wider range than previous scales. Quantitative result illustrates the new items are acceptable. Finally requirement for further factor analysis is suggested.