A laser device for the selective treatment of acne comprising: a laser source (1) terminating in an optical collimator (2), which supplies a laser beam； said laser source (1) comprises a switch (13) which allows impulses of said laser beam with pre-defined duration to be transmitted； an opto-mechanical interface (3) comprising a lens (4) focusing the laser beam received from the optical collimator (2)； an optical fibre (5) connected to said opto-mechanical interface (3)； characterized in that said optical fibre (5) has a length greater than 15 m； and said device comprises a handpiece (10) connected to said optical fibre (5) where said handpiece (10) comprises an optical zoom system (11) which allows the diameter of the laser beam emerging from said handpiece (10) to be varied from 0.5 mm to 5 mm.
