This dust collecting unit for use in a cleaner includes an inlet port through which air and dust is taken in, a dust catch room into which the air and dust taken in through the inlet port is led, an air flow path for separating a part of air taken in through the inlet port and ensuring air flow, an air outlet port through which the air having passed through the dust catch room and the air flow path is discharged, and a filter provided on the upstream side of the air outlet port for preventing dust from flowing to the air outlet port from the dust catch room and the air flow path.