A projector comprising: an image forming panel that displays an image based on an original image; a projection optical system (11,96) that has, in order from a screen side, a first optical system, a first reflection member bending a first optical axis of the first optical system, a second reflection member configured to bend a second optical axis of a second optical system, and the second optical system, and projects the image displayed on the image forming panel onto a screen as a magnified image; a first connection member configured to connect the first optical system including the first reflection member to the second optical system to be rotationally movable around a second optical axis of the second optical system; a first sensor configured to detect a first rotational movement state of the first optical axis of the first optical system around the second optical axis in the first connection member; a third optical system that is disposed on the image forming panel side from the second reflection member; a second connection member configured to connect the second optical system and the second reflection member to the third optical system to be rotationally movable around a third optical axis of the third optical system; a second sensor configured to detect a second rotational movement state of the second optical axis of the second optical system around the third optical axis in the second connection member; and a controller (69,79) configured to change an orientation of a display image (E1, E11 to E18) of the image forming panel based on the first and second rotational movement states detected by the first sensor and the second sensor to make an orientation of a projection image (E21 to E24, E31 to E38) on a projection plane match the original image; wherein, in a case in which the controller (69,79) detects the first rotational movement state and the second rotational movement state on which the projection optical system (11,96) projects the image toward a ceiling direction or a floor direction, the controller (69,79) does not change the orientation of the display image (E1, E11 to E18). an image forming panel that displays an image based on an original image; a projection optical system (11,96) that has, in order from a screen side, a first optical system, a first reflection member bending a first optical axis of the first optical system, a second reflection member configured to bend a second optical axis of a second optical system, and the second optical system, and projects the image displayed on the image forming panel onto a screen as a magnified image; a first connection member configured to connect the first optical system including the first reflection member to the second optical system to be rotationally movable around a second optical axis of the second optical system; a first sensor configured to detect a first rotational movement state of the first optical axis of the first optical system around the second optical axis in the first connection member; a third optical system that is disposed on the image forming panel side from the second reflection member; a second connection member configured to connect the second optical system and the second reflection member to the third optical system to be rotationally movable around a third optical axis of the third optical system; a second sensor configured to detect a second rotational movement state of the second optical axis of the second optical system around the third optical axis in the second connection member; and a controller (69,79) configured to change an orientation of a display image (E1, E11 to E18) of the image forming panel based on the first and second rotational movement states detected by the first sensor and the second sensor to make an orientation of a projection image (E21 to E24, E31 to E38) on a projection plane match the original image; wherein, in a case in which the controller (69,79) detects the first rotational movement state and the second rotational movement state on which the projection optical system (11,96) projects the image toward a ceiling direction or a floor direction, the controller (69,79) does not change the orientation of the display image (E1, E11 to E18).