FIELD : medicine.SUBSTANCE : invention relates to medical equipment. Skin treatment device comprises a laser source, an optical system for focusing a laser beam on a target position below the skin surface and a plasma unit designed such that in use, at least part of the plasma penetrates the skin tissue to generate at least one free electron in the target position. Device also comprises a control unit for controlling the laser source and the plasma unit such that in use, at least part of the laser beam light is absorbed by said at least one free electron generated in the target position, thereby generating a multiphoton ionisation process, wherein the total intensity of the laser beam, required for the generation of a multiphoton ionisation process, is reduced compared to skin treatment devices, which generate a multiphoton ionisation process, using only a laser beam.EFFECT : skin treatment device for multiphoton ionisation-based skin treatment is disclosed.13 cl, 4 dwg