This optical disk device includes a pickup head, a spindle motor, a signal generation unit, a runout amount calculation unit, and an out of balance disk detection unit. The signal generation unit generates a tracking error signal. The runout amount calculation unit controls the rotational speed of the spindle motor to first and second disk rotational speeds, and obtains, at these rotational speeds, runout amounts TE1 and TE2 of a tracking error signal, and runout amounts FE1 and FE2 of a focus error signal. And an out of balance disk detection unit detects that this optical disk is an out of balance disk, if the absolute value of (TE2×FE2)/(TE1×FE1) is greater than or equal to a threshold value.