An obstacle touching detecting device for a swimming pool cleaner includes a main functional portion of the cleaner and a sensor obstacle touching detecting device. The main functional portion of the cleaner includes a cleaner main body, a controller module, and a power-driven actuating device. The controller module and the power-driven actuating device are connected to the cleaner main body. The sensor obstacle touching detecting device includes a trigger unit connected to the cleaner main body and a sensor detecting module electrically connected to the controller module. The controller module is electrically connected to the power-driven actuating device. The trigger unit works collaboratively with the sensor detecting module to trigger the sensor detecting module to generate a detection signal. An automatic detection is performed when the cleaner touches the wall or other obstacles, and the cleaner is controlled to change direction automatically.