Infusion device, particularly for machines for preparing an infusion beverage with a capsule containing an aromatic substance, comprising: - a first infusing member, - a second infusing member adapted for cooperating with said first infusing member; said second infusing member comprising a housing seat for a capsule-holder or a pod-holder; - said capsule-holder or pod-holder comprising a recess for at least partially accommodating an infusion capsule; - said capsule-holder or pod-holder being removably introducible in said housing seat; - said second infusing member being hinged to said first infusing member along a hinge axis (X-X) to rotate with respect to said first infusing member between a closed position, in which said second infusing member closes said first infusing member to define a capsule-holder or pod-holder inserted in said housing seat, an infusion chamber and a rotated open position in which said second infusing member is partially spaced from the first infusing member of a distance allowing the capsule-holder or pod-holder to be drawn out; - said second infusing member being hinged to said first infusing member so that the hinge axis (X-X) is free to pitch; characterised that it comprises - activating means adapted to activate the second infusing member for the rotation movement from the open position to the closed position, and vice versa; - said activating means comprise at least one pivot member and at least one curvilinear profile, - said pivot member takes the form of a manually operable lever operatively hinged to the first infusing member so that the rotation of said lever in a way entails the rotation of said at least one pivot member with respect to said curvilinear profile integral to said second infusing member and, consequently, the movement of the second infusing member from said open position to said closed position; - said at least one curvilinear profile is made so that its convexity faces said at least one pivot member. - a first infusing member, - a second infusing member adapted for cooperating with said first infusing member; said second infusing member comprising a housing seat for a capsule-holder or a pod-holder; - said capsule-holder or pod-holder comprising a recess for at least partially accommodating an infusion capsule; - said capsule-holder or pod-holder being removably introducible in said housing seat; - said second infusing member being hinged to said first infusing member along a hinge axis (X-X) to rotate with respect to said first infusing member between a closed position, in which said second infusing member closes said first infusing member to define a capsule-holder or pod-holder inserted in said housing seat, an infusion chamber and a rotated open position in which said second infusing member is partially spaced from the first infusing member of a distance allowing the capsule-holder or pod-holder to be drawn out; - said second infusing member being hinged to said first infusing member so that the hinge axis (X-X) is free to pitch; - activating means adapted to activate the second infusing member for the rotation movement from the open position to the closed position, and vice versa; - said activating means comprise at least one pivot member and at least one curvilinear profile, - said pivot member takes the form of a manually operable lever operatively hinged to the first infusing member so that the rotation of said lever in a way entails the rotation of said at least one pivot member with respect to said curvilinear profile integral to said second infusing member and, consequently, the movement of the second infusing member from said open position to said closed position; - said at least one curvilinear profile is made so that its convexity faces said at least one pivot member.