To provide a RISC module capable of easily and safely detaching an external device from an external device connecting port such as a C/F socket.

The RISC module 1 includes a CPU 11 processing a micro-code as a program code, a ROM 12 storing a program for IPL and the like, the C/F socket 20 capable of connecting and disconnecting with the external device 25 such as an external storage device, a substrate 23 equipped with the CPU 11, the ROM 12 and the C/F socket 20, and a contact connector 24 connected with a computer system 26 such as a workstation and a page printer. The external device 25 is attached so that all or part of the external device 25 protrudes from the periphery of the substrate 23. As a result, the external device 25 connected to the C/F socket 20 can be easily and safely detached.