An absorbent product, such as a sanitary towel, has a stiffening element which is intended to contribute to the three-dimensional shape of the product during its use. The optical pickup actuator according to the present invention comprises a moving part having an asymmetric structure with respect to the objective lens, and a driving force of the moving part is generated by a magnetic circuit constituting of permanent magnets, a yoke and coils. The amplifier also comprises a bypass circuit that is coupled to an output of the pre-driver.