A wiper device mounted on a vehicle, the wiper device configured to control a duty ratio in accordance with target speed of rotation to cause a wiper member (15a, 15b) to carry out a wiping-out operation on a window surface by using a motor, the target speed of rotation being instructed by an operation for a wiper switch, the wiper device comprising: a rotation speed detecting unit configured to detect speed of rotation of the motor; a PWM signal generating unit configured to control the duty ratio in a range lower than a duty ratio upper limit, and to generate a PWM signal to which the duty ratio is reflected; a lock detecting unit configured to carry out a predetermined protecting operation in a case where the speed of rotation detected by the rotation speed detecting unit is lower than a lock determination threshold value; and a condition setting unit configured to respectively set the duty ratio upper limit and the lock determination threshold value to a first upper limit and a first determination threshold value in a first case in which vehicle speed of the vehicle is lower than a vehicle speed determination threshold value defined in advance, the condition setting unit being configured to respectively set the duty ratio upper limit and the lock determination threshold value to a second upper limit higher than the first upper limit and a second determination threshold value lower than the first determination threshold value in a second case in which the vehicle speed is higher than the vehicle speed determination threshold value, characterised in that the predetermined protecting operation carried out by the lock detecting unit is an operation in which working of the motor is stopped, and in that the condition setting unit is configured to set a number of times of an after-wiping-out operation to a first number of times in the first case, the after-wiping-out operation being a wiping-out operation for window washer fluid on the window surface after the window washer fluid is injected onto the window surface, and the condition setting unit is configured to set the number of times of the after-wiping-out operation to a second number of times in the second case, the second number of times being smaller than the first number of times. a rotation speed detecting unit configured to detect speed of rotation of the motor; a PWM signal generating unit configured to control the duty ratio in a range lower than a duty ratio upper limit, and to generate a PWM signal to which the duty ratio is reflected; a lock detecting unit configured to carry out a predetermined protecting operation in a case where the speed of rotation detected by the rotation speed detecting unit is lower than a lock determination threshold value; and a condition setting unit configured to respectively set the duty ratio upper limit and the lock determination threshold value to a first upper limit and a first determination threshold value in a first case in which vehicle speed of the vehicle is lower than a vehicle speed determination threshold value defined in advance, the condition setting unit being configured to respectively set the duty ratio upper limit and the lock determination threshold value to a second upper limit higher than the first upper limit and a second determination threshold value lower than the first determination threshold value in a second case in which the vehicle speed is higher than the vehicle speed determination threshold value, characterised in that the predetermined protecting operation carried out by the lock detecting unit is an operation in which working of the motor is stopped, and in that the condition setting unit is configured to set a number of times of an after-wiping-out operation to a first number of times in the first case, the after-wiping-out operation being a wiping-out operation for window washer fluid on the window surface after the window washer fluid is injected onto the window surface, and the condition setting unit is configured to set the number of times of the after-wiping-out operation to a second number of times in the second case, the second number of times being smaller than the first number of times.