A first line head 1 and a second line head 2 are arranged in a scanning direction X. In each of the line heads 1 and 2, actuator blocks 40 are arranged at a constant interval in a head longitudinal direction Y so as to be spaced apart from one another. The actuator block 40 of the second line head 2 is located between the actuator blocks 40 and 40 of the first line head 1 with respect to the head longitudinal direction Y. The actuator block 40 of the first line head 1 and the actuator block 40 of the second line head 2 partially overlap with each other with respect to the head longitudinal direction Y.