A corrugated paperboard sheet feeding apparatus comprises: a plurality of sheet feeding rollers; a grate formed with a plurality of opening portions for receiving the sheet feeding rollers and configured to switch between contact and non-contact states of the corrugated paperboard sheet with respect to the sheet feeding rollers; and a suction box configured to suck the corrugated paperboard sheet downwardly by gaps between the sheet feeding rollers and the opening portions, wherein each of the gaps is formed to be 10 mm or less, and wherein the apparatus further comprises a mat switch for detecting an entry of a person into an area in a sheet feeding section, and a control device for stopping movement of the sheet feeding rollers and/or the grate when the mat switch is turned on.