To provide a semiconductor device, in which the circuit configuration can be simplified and the substrate can be miniaturized by sharing a memory among plural processing circuits and the convenience can be improved by directly utilizing the processing result mutually among the respective processing circuits.

This device is provided with a microcomputer 200 for controlling the operation of the entire device, a signal processing IC 100 for performing prescribed signal processing and a memory 300 shared by these processing circuits, and the microcomputer 200 and the signal processing IC 100 access the memory 300 through a common bus. When the signal processing IC 100 accesses the memory 300, a bus use request signal is transmitted to the microcomputer 200 and when the microcomputer 200 receives the bus use request signal and does not use the bus, a bus use permission signal is transmitted to the signal processing IC 100.