An embodiment of the present invention relates to a parking brake actuator which includes a motor; a worm gear connected to the motor to transmit a power; a worm wheel engaged with the worm gear; a drive shaft coupled to the worm wheel, wherein a parking cable is connected to the drive shaft; a power transmission gear including a first gear coupled to a rotational shaft of the motor and a second gear which is coupled to a rotational shaft of the worm gear and connected to the first gear to transmit the power; and a housing including a first accommodation portion disposed at one side of a reference line which is formed perpendicular to the rotational shaft of the motor and passes through the first gear to accommodate the motor, a second accommodation portion disposed at another side of the reference line to accommodate the worm gear so that the rotational shaft of the worm gear is parallel to the rotational shaft of the motor, and a third accommodation portion disposed at the other side of the reference line to accommodate the worm wheel, thus providing an advantageous effect in which motors of various sizes may be applied without machining a separate housing to correspond to each of the sizes of motor or changing sizes or the number of teeth of gears.