1. A task processing device comprising a task control circuit that manages an execution state of a plurality of tasks executed in a plurality of processors, wherein one or more of the processors transmit a system call signal to the task control circuit when executing a system call instruction, and wherein, upon receipt of a first system call signal from a first processor, the task control circuit executes a task switch of the first processor by: identifying a first task being executed in the first processor by referring to processor management information wherein a processor ID of a processor and a task ID of a task being executed in the processor are registered; selecting autonomously a second task that is to be executed subsequently; saving process data of the first task from a processing register of the first processor into a predetermined storage area; loading process data of the second task into the processing register of the first processor; and updating the processor management information.