A sheet cutter is operable by one hand for maintaining a sheet on a placing table and by other hand for cutting the sheet to ensure safety of finger of the one hand. The sheet cutter includes a pressing operating member adapted to be depressed from a non-pressing position to a pressing position for maintaining the sheet on the placing table against a biasing force of a spring, and a cutting operating member for travelling a cutter unit between one end and another end of the placing table, wherein the pressing operating member and the cutting operating member are arranged at different positions with a certain interval to set their operating directions orthogonal to each other. Accordingly, a sheet on the placing table can be cut by operating the cutting operating member horizontally with the other hand while operating the pressing operating member vertically with the one hand.