In image display devices using laser light, flickering with a minute speckle shape which is called speckle noise occurs due to the unique coherence (interference) of the laser light. In order to reduce the speckle noise, various methods have been proposed. As one of the methods, the Patent Literature 1 discloses a method which uses a spatial polarization control element to polarize beam components of the laser light in different directions. The polarization control element includes a first area (half-wave plate) and a second area (simple transmissive plate) and these areas are alternately arranged in the diametrical direction of the laser. Among P-polarized laser light components incident on the polarization control element, a beam component passing through the first area is S-polarized. On the other hand, a beam component passing through the second area is emitted as a P-polarized beam component without being polarized. In this way, the laser light passing through the polarization control element includes a P-polarized beam component and an S-polarized beam component. Since speckle patterns of P polarization and S polarization have a low correlation therebetween, the overlap therebetween makes it possible to reduce the speckle noise. In addition, the Patent Literature 2 discloses a method in which a half-wave plate is rotated by a motor to change the polarization direction of laser light passing through the wavelength plate over time. In this way, the speckle patterns with different polarization directions overlap each other over time and the speckle noise is reduced.