Disclosed are a position information input system capable of coupling a signal generating device and a signal receiving device to each other. Firstly, a coupling unit is formed at a signal receiving device. Under such configuration, a signal generating device and the signal receiving device can be coupled to each other once the signal generating device is coupled to the coupling unit. This can enhance portability and a storage characteristic of the position information input system. Secondly, a contact power switch is installed in the coupling unit. Under such configuration, if a user separates the signal generating device from the signal receiving device for input of position information, the contact power switch is automatically turned on. As a result, the signal receiving device is automatically turned on. On the contrary, if a user, who has completed the input of position information, couples the signal generating device to the signal receiving device, the contact power switch is automatically turned off. As a result, the signal generating device is automatically turned off. This can solve the conventional user's inconvenience, i.e., turning on a power switch for input of position information, and tuning off the power switch upon completion of the input of position information. This can enhance a user's convenience.