The invention relates to a monitoring device (1, 30) for lubricant quantities, particularly a monitoring device (1, 30) for lubricant quantities in a rotor head (2) of a helicopter (50) and more particularly a monitoring device (1, 30) for lubricant quantities in a rotor head (2) of a tail rotor (3) of a helicopter (50), comprising a casing (5) to preserve the lubricant quantities for monitoring, a shaft (6) mounted inside said casing to rotationally drive the casing (5), at least one bearing (11-14), said at least one bearing (11-14) being mounted from outside to the casing (5) and/or shaft (6) and said at least one bearing (11-14) being connected to the casing (5) for supply of lubricant, sensor means (19-22, 31-34) to detect the lubricant quantities inside said casing (5), and, interface means for communication of data from said sensor means (19-22, 31-34) to at least one display (54).