Apparatus for and method of controlling calender roll gap

The roll gap control system for a calender having first and second rolls (18, 19) rolling a raw material (B) includes a load measuring unit (11) for detecting a rolling load change between the first and second rolls (18, 19), a roll shaft position adjusting device (41) for increasing/decreasing a roll gap and a controller (46) for computing a roll gap change ( DELTA h) based on the rolling load change ( DELTA P) and for activating the roll shaft position adjusting device (41) to counterbalance the roll gap change ( DELTA h). A spring constant (k) of first and second rolls (18, 19) and mechanical members (24, 25, 28) supporting these rolls of the calender is calculated, and the rolling load change ( DELTA P) is divided by the spring constant (k). The quotient ( DELTA P/k) is the roll gap change ( DELTA h).