Projector that controls discharge lamp in response to deterioration

A projector that outputs a first image and a second image alternately while performing switching between the first image and the second image with given switching timing, comprising:

• a discharge lamp;
• a discharge lamp driving section that supplies, to the discharge lamp, a drive current that drives the discharge lamp;
• a state detecting section that detects a deteriorating state of the discharge lamp;
• and
• a control section that controls the discharge lamp driving section,
• wherein
• a period sandwiched between a time at which switching is performed and the next time at which switching is performed starts with a first period and ends with a second period,
• the control section controls the discharge lamp driving section so that the absolute value of the drive current becomes relatively small in the first period and relatively large in the second period, and
• in the second period,
• the control section controls the discharge lamp driving section so that the discharge lamp driving section supplies an alternating current to the discharge lamp as the drive current, and
• the control section controls the discharge lamp driving section so that at least part of the frequency of the drive current is decreased with the progress of the deteriorating state.