A method for installing a power window device, for use in a vehicle including a steering wheel and a plurality of doors, with each door having a window member, wherein the power window device is for raising and lowering each window member, the power window device including a plurality of drive units respectively mountable in the plurality of doors and operable for raising and lowering the associated window members, each of the drive units includes a data writeable non-volatile memory device and a processor, the data-writeable non-volatile memory device is configured to retain mounting position information (Da) before the associated drive unit is installed in the vehicle, the mounting position information is written to the memory device by a writing device to indicate a position in the vehicle at which the window member driven by the associated drive unit is located; the processor connected to the memory device, the processor is configured to retrieve steering wheel position information (Db) after the associated drive unit is installed in the vehicle, the steering wheel position indicates whether the steering wheel is located on the right or left side of the vehicle, the processor recognizing the position in the vehicle at which the associated drive unit is installed based on the mounting position information and the steering wheel information; the method being characterized by: mounting the plurality of drive units respectively on the plurality of doors operable for raising and lowering the associated window members; preparing the memory devices respectively for the plurality of drive units; retaining the mounting position information(Da), in each of the memory devices before the associated drive unit is installed in the vehicle, of a position in the vehicle at which the window member driven by the associated drive unit is located; preparing the plurality of processors connected to the associated memory devices respectively for the plurality of drive units; retrieving the steering wheel position information(Db), with each of the processors after the associated drive unit is installed in the vehicle, of whether the steering wheel is located on the right or left side of the vehicle; and recognizing the position in the vehicle at which the associated drive unit is installed with each of the processors based on the mounting position information and the steering wheel information. mounting the plurality of drive units respectively on the plurality of doors operable for raising and lowering the associated window members; preparing the memory devices respectively for the plurality of drive units; retaining the mounting position information(Da), in each of the memory devices before the associated drive unit is installed in the vehicle, of a position in the vehicle at which the window member driven by the associated drive unit is located; preparing the plurality of processors connected to the associated memory devices respectively for the plurality of drive units; retrieving the steering wheel position information(Db), with each of the processors after the associated drive unit is installed in the vehicle, of whether the steering wheel is located on the right or left side of the vehicle; and recognizing the position in the vehicle at which the associated drive unit is installed with each of the processors based on the mounting position information and the steering wheel information.