To control overrun of a blade during inversion while suppressing variations of a wiping cycle.

An elapsed time t and a target rotational speed TR of a motor are obtained (S1, S2), and a current position of a blade and a current rotational speed of the motor are calculated (S3, S4). A current state of the blade is determined (S5), and motor rotational speed is appropriately corrected based thereon (S6-S11). Firstly, a correction value CN of the motor rotational speed is calculated (S6), and a correction target rotational speed CTR is set from the correction value CN and the target rotational speed TR. Also, a correction addition upper limit value α is calculated (S8), and an upper limit rotational speed ULR is calculated by adding the target rotational speed TR to the value α so as to compare the upper limit rotational speed ULR with the correction target rotational speed CTR (S9). When the CTR is larger than the ULR, the upper limit rotational speed ULR is set as a final target rotational speed FTR (S11). Therefore, the increase of the motor rotational speed is suppressed and the speed of the blade during inversion is suppressed.

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