The present invention enables replacement work of a wiper motor to be carried out with a link plate being fixed to an output shaft, and achieves improvement of maintainability. A diameter dimension of a through-hole of a motor bracket is set to that of allowing a tip side of a link plate with a ball joint to pass through the through-hole in a state where the link plate is inclined with respect to the motor bracket. Thus, the replacement work of the wiper motor can be carried out with the link plate being fixed to the output shaft. Alignment work of the link plate with respect to the output shaft becomes unnecessary at a time of the replacement work of the wiper motor, and maintainability can be significantly improved without decreasing positional accuracy of wiper members with respect to a front glass.