a text data storage unit configured to store a plurality of text data, each text data having attribute data and time data, the attribute data being predetermined items;

a dictionary storage unit configured to hierarchically store a concept class as the highest node, a key concept as an event, and expressions of text data as the lowest node;

an analysis condition indication unit configured to indicate an analysis target as attribute data and an analysis condition as an event sequence;

a time series data generation unit configured to extract characters matched with an expression stored in the dictionary storage unit from each of the plurality of text data, to assign the event to which the expression belongs, to the text data including the characters, to extract a group of text data each having the same attribute data as the analysis target from the plurality of text data, and to generate time series data each representing the event assigned to the text data of the group in order of the time data of the text data;

a time series data analysis unit configured to count the number of the time series data each having the same event sequence as the analysis condition for each group; and

an analysis result output unit configured to output the number of the time series data for each group as an analysis result of said time series data analysis unit.