All infusion device (1) for administering a medical fluid to a patient comprises a receptacle (11) for receiving a syringe (2), a pusher device (12) movable in a pushing direction (P) for acting onto a piston (21) of the syringe (2) received in the receptacle (11), a driving rod (14), an electric drive device (141) for driving the driving rod (14), and a clutching device (13) comprising a frame member (131) and at least one clutch element (130A, 130B) movably arranged on the frame member (131). The at least one clutch clement (130A, 130B) is constituted to operatively connect, in a clutched stole, the driving rod (14) to the pusher device (12) for driving the pusher device (12) by the electric drive device (141). The clutching device (13) is actuatable to assume an unclutchcd state in which the operative connection between the driving rod (14) and the pusher device (12) is released. Herein the clutching device (13) comprises a lock element (19) for locking the at least one clutch element (130A, 130B) in the clutched state. In this way, an infusion device is provided which in an easy and reliable manner allows for maintaining the clutching device in the clutched state during operation of the infusion device.