A projection apparatus comprising: light source means configured to emit a first primary color, a second primary color, and a third primary color, said light source means including a first semiconductor light-emitting element emitting the first primary color, and a second semiconductor light-emitting element emitting the second primary color; input means configured to input a video signal; projecting means (14, 16, 17) configured to form, according to the video signal input by the input means, a sync field (Sync) to control the timing for the projection of a stereoscopic image, a first image field corresponding to the first primary color, a second image field corresponding to the second primary color, and a third image field corresponding to the third primary color, wherein said projecting means (14, 16, 17) is further configured to project said fields in time-division, using said primary colors emitted by the light source means; light source control means configured to simultaneously drive the first and the second semiconductor light-emitting elements (18, 19) during the sync field (Sync) thereby generating a secondary color having a luminance level; and gradation control means configured to gamma-correct a gradation of the first image field, a gradation of the second image field and a gradation of the third image field, wherein, when gamma-correcting the image field having a primary color complementary to said secondary color, the gradations ranging from zero to a gradation according to the luminance level of the sync field (Sync) are corrected to a specific gradation, such that it cancels out the secondary color of the sync field (Sync). light source means configured to emit a first primary color, a second primary color, and a third primary color, said light source means including a first semiconductor light-emitting element emitting the first primary color, and a second semiconductor light-emitting element emitting the second primary color; a first primary color, a second primary color, and a third primary color, a first semiconductor light-emitting element emitting the first primary color, and a second semiconductor light-emitting element emitting the second primary color; input means configured to input a video signal; projecting means (14, 16, 17) configured to form, according to the video signal input by the input means, a sync field (Sync) to control the timing for the projection of a stereoscopic image, a first image field corresponding to the first primary color, a second image field corresponding to the second primary color, and a third image field corresponding to the third primary color, wherein said projecting means (14, 16, 17) is further configured to project said fields in time-division, using said primary colors emitted by the light source means; a sync field (Sync) to control the timing for the projection of a stereoscopic image, a first image field corresponding to the first primary color, a second image field corresponding to the second primary color, and a third image field corresponding to the third primary color, wherein said projecting means (14, 16, 17) is further configured to project said fields in time-division, using said primary colors emitted by the light source means; light source control means configured to simultaneously drive the first and the second semiconductor light-emitting elements (18, 19) during the sync field (Sync) thereby generating a secondary color having a luminance level; and gradation control means configured to gamma-correct a gradation of the first image field, a gradation of the second image field and a gradation of the third image field, wherein, when gamma-correcting the image field having a primary color complementary to said secondary color, the gradations ranging from zero to a gradation according to the luminance level of the sync field (Sync) are corrected to a specific gradation, such that it cancels out the secondary color of the sync field (Sync).