To provide a polarizer and polarizing plate having improved durability, and to provide a method for producing the polarizer and the polarizing plate.

The polarizing plate composed of a polarizer which is made of hydrophilic polymer containing at least one dichroic dye and silicon or a silicon compound is disclosed. The polarizing plate is suppressed in transmittance change in a light resistance test using light of high intensity such as light of an ultra high-pressure mercury lamp. The polarizing plate is also suppressed in transmittance change in a heat resistance test. A liquid crystal projector exhibiting stable performance after long use can be obtained by using the polarizing plate.