To provide a method for fuel-injection control of a multi-cylinder diesel engine by which combustion noise characteristic of a diesel engine can be easily suppressed at reduced cost.

This method refers to control of fuel-injection in a four-cylinder diesel engine. In respective cylinders (#1-#4) of the diesel engine, a standard fuel-injection quantity Q is set on the basis of operation conditions of the engine. To any cylinder out of the respective cylinders (#1-#4), the fuel-injection quantity is increased/decreased by a slight quantity of (+q)/(-q) respectively, and any cylinder is changed every specified period of time (steps S10-S17). By balancing the quantity of increase (+q) or the quantity of decrease (-q) in any cylinder, reduction in fuel efficiency can be suppressed.