Brewing device for preparing beverages by mixing a pressurized flow with an edible substance provided inside of a capsule, whereby said brewing device presents from upstream to downstream: - a force transmission disposition adapted so that can convert a swivelling movement in a first direction around a rotation axis, into a piston-like linear movement along a displacement course between an upstream position where the brewing device is open, and a downstream position where the brewing device is closed, and vice-versa, - an injection disposition provided in connection with said force transmission disposition so that can be moved in a piston-like manner along the longitudinal direction of the brewing device, between an open position and a closed position thereof, and vice-versa, - a collection disposition arranged in stationary manner at a downstream position and adapted for retaining said capsule, presenting a collection chamber with upstream-oriented opening, and a discharge opening providing downstream fluid connection, - a structural disposition that provides support to said force transmission disposition, - whereby said injection disposition presents side supports adapted for supporting said capsule and provided sideways on both sides as grooves developing along a vertical direction and with inwards-oriented openings adapted to retain a part of said capsule, for example a collar-like radial projection, in a position generally aligned with the introduction onto said collection chamber, and - whereby said injection disposition further presents a support base provided on the downwards-oriented side of said injection disposition and extending beyond thereof, so as to provide support to a downwards-oriented part of said capsule, characterized in that said base support is provided so that can be moved together with said injection disposition, and be retained relative to said injection disposition, so that said base support only provides support to said capsule along an upstream part of the displacement course of said injection disposition. - a force transmission disposition adapted so that can convert a swivelling movement in a first direction around a rotation axis, into a piston-like linear movement along a displacement course between an upstream position where the brewing device is open, and a downstream position where the brewing device is closed, and vice-versa, - an injection disposition provided in connection with said force transmission disposition so that can be moved in a piston-like manner along the longitudinal direction of the brewing device, between an open position and a closed position thereof, and vice-versa, - a collection disposition arranged in stationary manner at a downstream position and adapted for retaining said capsule, presenting a collection chamber with upstream-oriented opening, and a discharge opening providing downstream fluid connection, - a structural disposition that provides support to said force transmission disposition, - whereby said injection disposition presents side supports adapted for supporting said capsule and provided sideways on both sides as grooves developing along a vertical direction and with inwards-oriented openings adapted to retain a part of said capsule, for example a collar-like radial projection, in a position generally aligned with the introduction onto said collection chamber, and - whereby said injection disposition further presents a support base provided on the downwards-oriented side of said injection disposition and extending beyond thereof, so as to provide support to a downwards-oriented part of said capsule,