Abstract: The present invention relates to a device for interior flushing of spaces in tanks or containers. At least one rotatable part (8) of a pipe (6, 8, 11) for the supply of flushing liquid (7) is provided in the space (2) and said rotatable part (8) has at least one flushing nozzle (9) for discharging jets (10) of flushing liquid. A driving or operating device (22) is provided to rotate said rotatable part (8) about a geometric rotation axis (R1A) and the flushing nozzle (9) about another geometric rotation axis (R2A). The driving device (22) is provided to be brought to rotate in opposite rotary directions (R1, R2) by reversing its rotary direction. A switch device (23) is provided to bring either said rotatable part (8) or the flushing nozzle (9) to rotate in dependence of the rotary direction (R1 or R2) of the driving device (22). A control device (48) is provided to control the driving device (22) to rotate in one or the opposite rotary direction (R1 or R2).