Projection type display apparatus and control method for projection type display apparatus

A projection type display apparatus comprising:

• a light source;
• a light separation device that includes a plurality of transmission areas on which light from the light source is made incident and which each transmit light of a different wavelength;
• a detector that detects ambient information;
• a power supplier that supplies power to the light source;
• and
• a controller that controls a supply power to be supplied to the light source by the power supplier, wherein
• the transmission areas, on which light from the light source is made incident, are sequentially changed, and
• when the ambient information satisfies a predetermined condition, the controller changes the supply power in synchrony with changes in the plurality of transmission areas.