A dust collecting system includes a power tool and a dust collector. The power tool is configured to perform processing operation on a workpiece by driving a tool accessory. The dust collector is configured to collect dust generated by the processing operation. The power tool includes a first motor and a driving mechanism configured to drive the tool accessory by power of the first motor. The dust collector includes a second motor and a fan configured to be rotationally driven by the second motor to generate air flow for collecting dust. The dust collecting system includes a first control device configured to control a rotation speed of the second motor according to a driving state of the power tool.