A connection device, comprising: a storage unit (120; 121-123) for storing type priority level information for specifying a priority level assigned in advance for each type of a process, usable communication system information for specifying a usable communication system for each process, and sharing propriety information for specifying whether or not the communication system is sharable among a plurality of processes during a same period of time; a plurality of communication units adapted to communicate with another device with use of communication systems different from one another; and a communication system allocation control unit configured to: use the usable communication system information to identify the communication system usable by the process to be started to be executed; allocate, when the identified communication system is not sharable and a process in execution that is different from the process to be started to be executed already uses the identified communication system, the process to be started to be executed to use the communication system based on priority levels of the process in execution and the process to be started to be executed; and characterized in that, when there is a change in a configuration in the another device, the communication system allocation control unit is adapted to acquire information to specify the communication system, which is compatible with the another device after the change in the configuration in the another device, from a predetermined server device and to update the usable communication system information. a storage unit (120; 121-123) for storing type priority level information for specifying a priority level assigned in advance for each type of a process, usable communication system information for specifying a usable communication system for each process, and sharing propriety information for specifying whether or not the communication system is sharable among a plurality of processes during a same period of time; a plurality of communication units adapted to communicate with another device with use of communication systems different from one another; and a communication system allocation control unit configured to: use the usable communication system information to identify the communication system usable by the process to be started to be executed; allocate, when the identified communication system is not sharable and a process in execution that is different from the process to be started to be executed already uses the identified communication system, the process to be started to be executed to use the communication system based on priority levels of the process in execution and the process to be started to be executed; and use the usable communication system information to identify the communication system usable by the process to be started to be executed; allocate, when the identified communication system is not sharable and a process in execution that is different from the process to be started to be executed already uses the identified communication system, the process to be started to be executed to use the communication system based on priority levels of the process in execution and the process to be started to be executed; and characterized in that, when there is a change in a configuration in the another device, the communication system allocation control unit is adapted to acquire information to specify the communication system, which is compatible with the another device after the change in the configuration in the another device, from a predetermined server device and to update the usable communication system information.