Abstract: The invention relates to a maintenance apparatus (1) for medical or dental handpieces (17), having a housing (2), which encloses a free maintenance chamber (4) which is accessible by means of a door (5), having a plurality of connection parts (16a, 16b) in the maintenance chamber (4) each for receiving the rearward end of a handpiece (17), having a supply line (18) for a maintenance medium, which branches with supply line branches (18a) to the connection parts (16a, 16b), which branches open out each at a mouth opening (16a1, 16b1) at the associated connection part (16a, 16b), which stands in connection with a drive channel of the connected handpiece (17), having a supply system for supplying the maintenance medium to the connection parts (16a, 16b) and having a control device (51) for control of the supply system, whereby a sensor (S2a to S2d) is associated with each connection part (16a, 16b, 16c), which sensor is activated by means of the handpiece (17) connected with the associated connection part and emi