To filter out a noise and control influence of noise on an external circuit by providing a noise filter circuit in an output circuit to filter out the noise which propagates to an external circuit through a wiring.

When a potential of a contact Y is reduced, a PMOS transistor 202 in a noise filter circuit 20 turns on to connect the potential of contact Y to the power source voltage VEXT. Therefore, potential of the contact Y is increased up to VEXT and change of the potential of contact Y by a noise can be removed. Next, potential of the contact X also rises owing to the influence of the noise. However, an NMOS transistor 204 in the noise reduction circuit 20 turns on and the contact Y is connected to the power source voltage VEXT. Thereby, change of potential of the contact Y due to noise can be removed as explained above.