A printer is capable of stably feeding even a thin recording medium to a printing section and obtaining good print quality similar to that obtainable in the case of a thick recording medium. The printer comprises a first supply path for supplying a first recording medium, a second supply path for supplying a second recording medium thicker than the first recording medium, a printing section for printing on a recording medium supplied from the first supply path or the second supply path, and a delivery section for delivering the recording medium printed in the printing section. A guide spring member which is movable up and down is projected upstream of the printing section and in a meeting portion of the first supply path and the second supply path. This guide spring member serves to support a top surface of the first recording medium at a predetermined height.