An acoustic wave filter device which attains improved balancing between transmission characteristics of first and second balanced terminals includes first and second 3-IDT longitudinally coupled resonator type acoustic wave filter elements that are connected to an unbalanced terminal in parallel, and one terminal of a first IDT and one terminal of a fourth IDT are connected to each other and further connected to the unbalanced terminal, second and third IDTs are connected to each other and further connected to a first balanced terminal, fifth and sixth IDTs are connected to each other and further connected to a second balanced terminal, and a first ground line which electrically connects the second IDT which is nearer to a first ground terminal than the third IDT to the second ground terminal is longer than a second ground line which electrically connects the fifth IDT which is nearer to the first ground terminal than the sixth IDT to the first ground terminal.