A log collecting apparatus includes: a response data forwarding unit to respond to a trace log request; a determining unit determines whether the ratio of error logs versus unsent trace logs is equal to or greater than a predetermined threshold value; a differential trace log creator configured to create differential trace logs, wherein the duplicate error logs have been deleted from the unsent trace logs, when it is determined that the error log ratio is equal to or greater than the predetermined threshold value; and a response data configuration unit configured to set response data with the differential trace logs, and to set the response data with the unsent trace logs when the error log ratio is not equal to or greater than the predetermined threshold value.