To provide a data collection system wherein a period and contents of measurement data can be easily designated as extraction conditions.

The data collection system 5 is comprised of two or more data collection slave units 2 acquiring measurement data, and a data collection master unit 1 collecting the measurement data acquired by each data collection slave unit 2. The data collection master unit 1 is provided with a data collection part 13 collecting the measurement data and date and time information from the data collection slave units 2, a database storing the collected measurement data, and a data extracting part 11 extracting measurement data from the database. The data collection part 13 determines date and time information for extraction. The data extracting part 11 is provided with a means for collating the date and time information for extraction with predetermined extraction conditions, and carrying out extraction of a data record.