1. An information processing device which specifies a library function invoked to generate output data, the information processing device comprising: a library function execution monitoring unit which, when an analysis log of a monitoring target program is generated, captures a library function invoked by the monitoring target program, and sets a tag for uniquely identifying the invocation of the library function, to the output data from the library function every time the library function is invoked; a log storage unit which stores the analysis log including the output data from the library function; and a log searching unit which specifies a library function invoked to generate the output data from the information processing device by using as a key the tag set to the analysis log stored in the log storage unit.