Actuating device for mechanically actuating a component of a machine, - comprising a housing, which has a first housing part and a second housing part, - an electric motor arranged in the housing for driving an actuator arranged on the outside of the housing for coupling with the component to be actuated, - a cooling channel formed in the housing for a liquid coolant, which is fluidically connected to a coolant inlet connection provided on the outside of the housing and to a coolant outlet connection provided on the outside of the housing, - wherein the electric motor has a casing in circumferential direction, is arranged in the second housing part and projects axially into the first housing part at least with its drive shaft, - wherein the cooling channel is provided on the second housing part, characterised in that - the first housing part is made of plastic, - a sheet metal shell is inserted axially into the second housing part, - the electric motor is inserted axially in the sheet metal shell, - the cooling channel is formed radially between the sheet metal shell and the second housing part, - a casing of the sheet metal shell surrounding the electric motor in circumferential direction bears directly radially on the casing of the electric motor, - the second housing part is made of plastic, - the cooling channel is delimited radially on the outside directly by a peripheral wall of the second housing part surrounding the electric motor in circumferential direction, - the coolant inlet connection is provided on one housing part (4, 5), whereas the coolant outlet connection is provided on the other housing part (4, 5). - comprising a housing, which has a first housing part and a second housing part, - an electric motor arranged in the housing for driving an actuator arranged on the outside of the housing for coupling with the component to be actuated, - a cooling channel formed in the housing for a liquid coolant, which is fluidically connected to a coolant inlet connection provided on the outside of the housing and to a coolant outlet connection provided on the outside of the housing, - wherein the electric motor has a casing in circumferential direction, is arranged in the second housing part and projects axially into the first housing part at least with its drive shaft, - wherein the cooling channel is provided on the second housing part, characterised in that - the first housing part is made of plastic, - a sheet metal shell is inserted axially into the second housing part, - the electric motor is inserted axially in the sheet metal shell, - the cooling channel is formed radially between the sheet metal shell and the second housing part, - a casing of the sheet metal shell surrounding the electric motor in circumferential direction bears directly radially on the casing of the electric motor, - the second housing part is made of plastic, - the cooling channel is delimited radially on the outside directly by a peripheral wall of the second housing part surrounding the electric motor in circumferential direction, - the coolant inlet connection is provided on one housing part (4, 5), whereas the coolant outlet connection is provided on the other housing part (4, 5).