A printing medium supply device comprising: a pickup roller configured to come into contact with a printing medium; a pickup holder configured to support the pickup roller, the pickup holder being rotated about a shaft to lift or lower the pickup roller, and the pickup holder includes: a holder body configured to be pivotally rotated about the shaft, a holder rotating portion coupled to the shaft at one side of the holder body, and a holder support portion configured to support the pickup roller at the other side of the holder body; a link member fixed to the holder rotating portion of the pickup holder so as to be pivotally rotated about the shaft along with the pickup holder; a pressure member coming into contact with a pressure applied portion of the link member to rotate the link member by applying pressure to the link member; an elastic member elastically supported by the pressure member to transmit elastic force to the link member; and a tray on which printing media is loaded, wherein the pickup roller has a variable vertical position depending on the quantity of printing media loaded on the tray, and a distance from the centre of the shaft to the pressure applied portion of the link member varies based on a position of the pickup roller, and comprises a first distance, r1, when the pickup roller is located at a first position spaced apart from the tray, and a second distance, r2, when the pickup roller is located at a second position lower than the first position and comes into close contact with the tray, and r2 is greater than r1. a pickup roller configured to come into contact with a printing medium; a pickup holder configured to support the pickup roller, the pickup holder being rotated about a shaft to lift or lower the pickup roller, and the pickup holder includes: a holder body configured to be pivotally rotated about the shaft, a holder rotating portion coupled to the shaft at one side of the holder body, and a holder support portion configured to support the pickup roller at the other side of the holder body; a holder body configured to be pivotally rotated about the shaft, a holder rotating portion coupled to the shaft at one side of the holder body, and a holder support portion configured to support the pickup roller at the other side of the holder body; a link member fixed to the holder rotating portion of the pickup holder so as to be pivotally rotated about the shaft along with the pickup holder; a pressure member coming into contact with a pressure applied portion of the link member to rotate the link member by applying pressure to the link member; an elastic member elastically supported by the pressure member to transmit elastic force to the link member; and a tray on which printing media is loaded, wherein the pickup roller has a variable vertical position depending on the quantity of printing media loaded on the tray, and a distance from the centre of the shaft to the pressure applied portion of the link member varies based on a position of the pickup roller, and comprises a first distance, r1, when the pickup roller is located at a first position spaced apart from the tray, and a second distance, r2, when the pickup roller is located at a second position lower than the first position and comes into close contact with the tray, and r2 is greater than r1.