An electronic musical apparatus for training to play the apparatus in correct timing comprises a play timing notifying device which notifies reference time points in a music progression for operating the apparatus to play music, an operation detecting device for detecting each of player's operations on the apparatus as a player operates the apparatus with reference to the reference time points, a time deviation detecting device for detecting a time deviation of each of the player's operations from corresponding one of the reference time points, a tolerance range setting device for setting a tolerance range with respect to each of the reference time point by taking into consideration a plurality of the past detected time deviations, the tolerance range being for evaluating whether a detected time deviation falls within the tolerance range or not, and a tone generation control device which controls generation of tones for the player's operations differently according to whether each detected time deviation falls within the tolerance range or not. The tolerance range is set automatically based on the plurality of past detected time deviations. The tolerance range is divided into an advance margin and a delay margin about the reference time point, which two margins are preferably set separately. The detected time deviations are shown on a display screen in reference to the reference time points.