A pinch detection device at an opening/closing section has a very simple structure that can surely detect a pinch without faulty operation in a vehicle whose power supply voltage greatly fluctuates. The pinch detection device includes a sensor for detecting displacement of an opening/closing section of a vehicle to be opened/closed by a motor, and a time counter for counting a relative time adjusted according to a fluctuation in a power supply voltage. The pinch detection device also has a pinch detector for detecting a pinch of a foreign matter at the opening/closing section according to a change in a relative speed obtained based on a change in the displacement on a basis of the relative time.