Allocation of slots to different styluses is flexibly changed in units of the slot that is shorter than a frame. A stylus bi-directionally transmits and receives signals to and from a sensor controller connected to a sensor via capacitive coupling. The stylus includes a memory that temporarily stores a value of a local ID. The stylus includes a controller that determines whether or not a detected uplink signal includes the value of the local ID stored in the memory every time the uplink signal transmitted by the sensor controller is detected. The controller, in response to determining the detected uplink signal includes the value of the local ID stored in the memory, generates a downlink signal that is based on an operation state and transmits the downlink signal to the sensor controller.