The invention provides a diagnostic device of elevator comprising test data collecting part (33) which collects the action data of each part of the elevator when normally runs as the test data by a certain collecting period T; appointing test data extracting part (37) which extracts the test data of the test item from the test data collected by the test data collecting part (33) by the test period T, aiming at the test item for collecting the missed test data, executes the automatic test when the test period T is finished, solves the test data and sends the solved test data and the test data extracted data in advance to the monitoring center (7).