Function point analysis (FPA) was proposed to help measure the functionality of software systems. It is used to estimate the effort required for the software development. However, it has been reported that since function point measurement involves judgment on the part of the measurer, differences for the same product may occur even in the same organization. Also, if an organization tries to introduce FPA, FP will have to be measured from the past software developed there, and this measurement is cost-consuming. In this paper, we intend to examine the possibility to measure FP from source code automatically. At first, we propose measurement rules to count data and transactional functions for object-oriented program based on IFPUG method and develop the function point measurement tool. Then, we have applied the tool to practical Java programs in a computer company and examined the difference between the FP values obtained by the tool and those of an FP measurement specialist. As the results, the number of data and transactional functions extracted by the tool is similar to ones by the specialist though for the classification of each function there is some difference between them.