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. <EOS>