Cosmetics dispenser in the shape of a pen for discharging a cosmetics medium, wherein the dispenser is intended to be handled like a pen in order to be able to discharge the precisely required quantity of the medium at the desired location, with - an elongate housing extending in a main direction of extent, - a discharge opening at a front end of the housing, - a liquid reservoir arranged inside the housing, and - a pump mechanism arranged inside the housing, which pump mechanism can be actuated via an actuating button arranged on a jacket surface of the housing and has a pump chamber which is connected to the liquid reservoir at an inlet side and to the discharge opening at an outlet side, wherein - the pump chamber is delimited at least in parts by a dimensionally flexible wall, of which the outer surface forms the actuating button, characterized in that - the dimensionally flexible wall surrounds the pump chamber circumferentially and has openings only at the inlet side and the outlet side, - housing sections of the housing, provided on both sides of the actuating button in relation to the main direction of extent, are designed as rigid housing sections and are connected to one another by a likewise rigid connecting section, - the connecting section surrounds the dimensionally flexible wall circumferentially and has a recess through which the actuating button can be actuated, and forms a counterforce surface arranged in the circumferential direction on the side of the housing opposite the actuating button, and - an inlet valve designed as a pressure relief valve is provided between the liquid reservoir and the pump chamber and an outlet valve designed as a pressure relief valve is provided between the pump chamber and the discharge opening, wherein the inlet valve or the outlet valve is formed by valve surfaces configured integrally with the flexible wall, wherein the flexible wall has two lips which bear on each other when the pressure on both sides of the valve is equal and which disengage from each other in the event of overpressure or negative pressure in the pump chamber, and thus permit an outflow or inflow of medium. - an elongate housing extending in a main direction of extent, - a discharge opening at a front end of the housing, - a liquid reservoir arranged inside the housing, and - a pump mechanism arranged inside the housing, which pump mechanism can be actuated via an actuating button arranged on a jacket surface of the housing and has a pump chamber which is connected to the liquid reservoir at an inlet side and to the discharge opening at an outlet side, - the pump chamber is delimited at least in parts by a dimensionally flexible wall, of which the outer surface forms the actuating button, - the dimensionally flexible wall surrounds the pump chamber circumferentially and has openings only at the inlet side and the outlet side, - housing sections of the housing, provided on both sides of the actuating button in relation to the main direction of extent, are designed as rigid housing sections and are connected to one another by a likewise rigid connecting section, - the connecting section surrounds the dimensionally flexible wall circumferentially and has a recess through which the actuating button can be actuated, and forms a counterforce surface arranged in the circumferential direction on the side of the housing opposite the actuating button, and - an inlet valve designed as a pressure relief valve is provided between the liquid reservoir and the pump chamber and an outlet valve designed as a pressure relief valve is provided between the pump chamber and the discharge opening, wherein the inlet valve or the outlet valve is formed by valve surfaces configured integrally with the flexible wall, wherein the flexible wall has two lips which bear on each other when the pressure on both sides of the valve is equal and which disengage from each other in the event of overpressure or negative pressure in the pump chamber, and thus permit an outflow or inflow of medium.