A portable electronic device of the present invention includes a cabinet and a speaker placed inside the cabinet. The cabinet has one or more sound radiating holes in an area opposed to a front face of the speaker. A dustproof plate formed by attaching a dustproof net and a reinforcing sheet to each other is placed on the front face of the speaker or an inner face of the cabinet opposed to the front face. The reinforcing sheet has a plurality of openings formed for passing through sound waves from the speaker.