Apparatus for feeding bars to a machine tool, comprising: - a first end that is suitable for being placed in a position that is adjacent to a spindle of said machine tool; - stationary guiding and supporting means for supporting a bar in a first support region, said stationary guiding and supporting means extending along a longitudinal axis from a second end, opposite said first end, to an intermediate zone placed between said first end and said second end, - a drum element extending between said first end and said intermediate zone and rotatable around a rotation axis parallel to said longitudinal axis, - movable supporting means provided on said drum element and suitable for supporting a bar parallel to said longitudinal axis in a second support region adjacent to said first support region and extending between said intermediate zone and said first end, - said movable supporting means being slidably drivable along said drum element and parallel to said rotation axis between a contracted disengagement configuration, in which said movable supporting means are collected near said first end to enable a bar to be positioned on said stationary guiding and supporting means, and an extended engagement configuration, in which said movable supporting means are distributed between said first end and said intermediate zone to engage with said bar to be supported and guided, - wherein said first end is separated from said second end by a distance, said stationary guiding and supporting means extends for a first length which is shorter than said distance, and characterised in that said drum element extends for a second length which is shorter than said distance. - a first end that is suitable for being placed in a position that is adjacent to a spindle of said machine tool; - stationary guiding and supporting means for supporting a bar in a first support region, said stationary guiding and supporting means extending along a longitudinal axis from a second end, opposite said first end, to an intermediate zone placed between said first end and said second end, - a drum element extending between said first end and said intermediate zone and rotatable around a rotation axis parallel to said longitudinal axis, - movable supporting means provided on said drum element and suitable for supporting a bar parallel to said longitudinal axis in a second support region adjacent to said first support region and extending between said intermediate zone and said first end, - said movable supporting means being slidably drivable along said drum element and parallel to said rotation axis between a contracted disengagement configuration, in which said movable supporting means are collected near said first end to enable a bar to be positioned on said stationary guiding and supporting means, and an extended engagement configuration, in which said movable supporting means are distributed between said first end and said intermediate zone to engage with said bar to be supported and guided, - wherein said first end is separated from said second end by a distance, said stationary guiding and supporting means extends for a first length which is shorter than said distance, and characterised in that said drum element extends for a second length which is shorter than said distance.