The present disclosure discloses a seat base sliding device applied to a seat of a heavy machinery such as a loader, an excavator, or the like. The seat base sliding device includes: a seat base with a lower part is fixed to a floor of a vehicle body and an upper part at which a seat is installed; a sliding plate slidable inwards and outwards in a lateral direction of the seat base at both left and right sides of the seat base and in which a control stand is fixed to one side thereof; and at least one adjustment unit selectively fixing the sliding plate of which the position is determined by sliding movement to the seat base. The present disclosure is capable of preventing a cabin from knocking against both control stands of a seat device at the time of assembling the cabin around the seat device and in addition, preventing the corresponding control stands from interfering in a thigh of a driver at the time of operating a control lever of each control stand laterally after assembling the cabin.