A projection-type display device comprising: a light source unit that includes a plurality of a light-emitting elements of different colours (31, 32, 33), wherein the elements of different colours emit light sequentially; a reflection-type spatial optical modulation unit that includes a plurality of movable reflection elements an inclined state of which can be switched to either one of a first inclined state and a second inclined state, wherein the movable reflection element in the first inclined state reflects light of the light-emitting element in a direction where the light is projected as the light constituting an image, and wherein the movable reflection element in the second inclined state reflects light of the light-emitting element in a direction where the light is not projected as the light constituting the image; and a control unit that controls the reflection-type spatial optical modulation unit and the light source unit such that light constituting the image in accordance with a video signal to be input is projected, wherein the control unit divides respective frames of the image into a display period (Fa) that is a period when at least one element of the plurality of the light-emitting elements is caused to emit light, and a non-display period (Fb) that is a period when none of the plurality of the light-emitting elements is caused to emit light, wherein the display period and the non-display period are subdivided into subframes and for the display period, several subframes (SFa) for each colour of the light source exist wherein the subframes of each colour are concurrent to the emission time of the respective colour of the light source during the display period, wherein each subframe (SFa) of the display period is divided into a plurality of division display sub-frames (dSFa), and wherein for every division display sub-frame the movable reflection element state is controlled to be in the first or second inclined state, and wherein the control unit divides the plurality of the movable reflection elements in the reflection-type spatial optical modulation unit into a plurality of groups (160-1, 160-2), and determines, among the plurality of the division display sub-frames obtained by each display sub-frame being divided, the division display sub-frame in which the movable reflection element is fixed in the second inclined state, for each of the plurality of the groups of the plurality of the movable reflection elements. a light source unit that includes a plurality of a light-emitting elements of different colours (31, 32, 33), wherein the elements of different colours emit light sequentially; a reflection-type spatial optical modulation unit that includes a plurality of movable reflection elements an inclined state of which can be switched to either one of a first inclined state and a second inclined state, wherein the movable reflection element in the first inclined state reflects light of the light-emitting element in a direction where the light is projected as the light constituting an image, and wherein the movable reflection element in the second inclined state reflects light of the light-emitting element in a direction where the light is not projected as the light constituting the image; and a control unit that controls the reflection-type spatial optical modulation unit and the light source unit such that light constituting the image in accordance with a video signal to be input is projected, wherein the control unit divides respective frames of the image into a display period (Fa) that is a period when at least one element of the plurality of the light-emitting elements is caused to emit light, and a non-display period (Fb) that is a period when none of the plurality of the light-emitting elements is caused to emit light, wherein the display period and the non-display period are subdivided into subframes and for the display period, several subframes (SFa) for each colour of the light source exist wherein the subframes of each colour are concurrent to the emission time of the respective colour of the light source during the display period, wherein each subframe (SFa) of the display period is divided into a plurality of division display sub-frames (dSFa), and wherein for every division display sub-frame the movable reflection element state is controlled to be in the first or second inclined state, and wherein the display period and the non-display period are subdivided into subframes and for the display period, several subframes (SFa) for each colour of the light source exist wherein the subframes of each colour are concurrent to the emission time of the respective colour of the light source during the display period, wherein each subframe (SFa) of the display period is divided into a plurality of division display sub-frames (dSFa), and wherein for every division display sub-frame the movable reflection element state is controlled to be in the first or second inclined state, and wherein the control unit divides the plurality of the movable reflection elements in the reflection-type spatial optical modulation unit into a plurality of groups (160-1, 160-2), and determines, among the plurality of the division display sub-frames obtained by each display sub-frame being divided, the division display sub-frame in which the movable reflection element is fixed in the second inclined state, for each of the plurality of the groups of the plurality of the movable reflection elements.