A power control device for a pressing iron includes a position sensor that has a casing, an optical coupler and a shielding plate. The optical coupler is mounted in a lower part of the casing, and has a photoemitter and a photoreceiver that faces the photoemitter and that forms a clearance therewith. The shielding plate is received in the casing, and has an upper plate portion pivoted to an upper part of the casing, and a lower plate portion that extends into the clearance of the optical coupler. The lower plate portion is formed with a notch to permit light transmission between the photoemitter and the photoreceiver when the pressing iron is in an ironing position. The shielding plate pivots by virtue of gravity such that the notch is moved out of alignment with the photoemitter and the photoreceiver, and such that the lower plate portion blocks the light transmission between the photoemitter and the photoreceiver when the pressing iron is in a resting position.