An electronic musical instrument with an automatic chord performance device is of a type in which chord tones of plural series of different tone colors in different rhythm patterns are produced. This instrument employs a memory for storing a plurality of patterns per one rhythm and for plural rhythms in order to simultaneously obtain the chord tones of plural series per one rhythm. The patterns are read from the memory as tone generation timing signals. These tone generation timing signals control the amplitudes of the envelopes of the chord tone signals. The chord tone signals thus controlled in amplitude are generated after being controlled in the tone color in each of the series.