A terminal device comprising: communication means capable of operating in a plurality of states that include a first state in which a connection with a base station device has been established, and a second state in which a connection with a base station device has not been established, but the base station device holds information regarding the terminal device; and control means; wherein the terminal device is characterized in that: after the communication means that has been operating with a first base station device in the first state starts operating in the second state, the control means is configured to determine whether or not predetermined information is held that enables the communication means to perform communication with the first base station device in the second state and that has been acquired from the first base station device in the first state, the control means is configured to determine whether or not a target to which a signal is to be transmitted has changed from the first base station device to a second base station device, in a case where it is determined (S603, S604) that the predetermined information is held and the target to which a signal is to be transmitted has not changed, the control means is configured to control, when communicating with the first base station device, the communication means to perform communication using the predetermined information without transitioning from the second state, and in a case where it is determined (S603, S604) that the predetermined information is held and the target to which a signal is to be transmitted has changed, the control means is configured to control, when communicating with the second base station device, the communication means to perform communication (S509, S606) with transitioning to the first state and without using the predetermined information. communication means capable of operating in a plurality of states that include a first state in which a connection with a base station device has been established, and a second state in which a connection with a base station device has not been established, but the base station device holds information regarding the terminal device; and control means; wherein the terminal device is characterized in that: after the communication means that has been operating with a first base station device in the first state starts operating in the second state, the control means is configured to determine whether or not predetermined information is held that enables the communication means to perform communication with the first base station device in the second state and that has been acquired from the first base station device in the first state, the control means is configured to determine whether or not a target to which a signal is to be transmitted has changed from the first base station device to a second base station device, in a case where it is determined (S603, S604) that the predetermined information is held and the target to which a signal is to be transmitted has not changed, the control means is configured to control, when communicating with the first base station device, the communication means to perform communication using the predetermined information without transitioning from the second state, and in a case where it is determined (S603, S604) that the predetermined information is held and the target to which a signal is to be transmitted has changed, the control means is configured to control, when communicating with the second base station device, the communication means to perform communication (S509, S606) with transitioning to the first state and without using the predetermined information. the control means is configured to determine whether or not predetermined information is held that enables the communication means to perform communication with the first base station device in the second state and that has been acquired from the first base station device in the first state, the control means is configured to determine whether or not a target to which a signal is to be transmitted has changed from the first base station device to a second base station device, in a case where it is determined (S603, S604) that the predetermined information is held and the target to which a signal is to be transmitted has not changed, the control means is configured to control, when communicating with the first base station device, the communication means to perform communication using the predetermined information without transitioning from the second state, and in a case where it is determined (S603, S604) that the predetermined information is held and the target to which a signal is to be transmitted has changed, the control means is configured to control, when communicating with the second base station device, the communication means to perform communication (S509, S606) with transitioning to the first state and without using the predetermined information.