An image-forming apparatus is provided which prevents irregularity of an image density and improves the life of heating elements. In a half of recording heads (a group of recording heads 22K2, 22K4, 22K6 not adjacent to each other), off time T2 is shortened at a timing of PWM renewal 1; in the other recording heads (22K1, 22K3, 22K5, another group of the recording heads not adjacent to each other) the off time T2 is not changed at the timing of PWM renewal 1 but is shortened at the timing of PWM renewal 2. As the result, in the region corresponding to the timing from PWM renewal 1 to PWM renewal 2, the amount of the ink droplets ejected from the nozzles of the recording heads 22K2, 22K4, 22K6 is decreased to decrease slightly invisibly the image density formed by the ink droplets ejected from the nozzles 22K2, 22K4, 22K6.