An image processing system for a vehicle (40, 40P, 40R), the image processing system comprising: a viewpoint image generating unit that generates a viewpoint image (GIb) viewed from a predetermined virtual viewpoint (Ep) when it is assumed that a surrounding image corresponding to surrounding image data is projected on a virtual projection plane (Sp, Spi), based on inclination information corresponding to an inclination of the vehicle and the surrounding image data obtained by capturing an image of a periphery of the vehicle, wherein the virtual projection plane (Sp, Sp1) is set to be three-dimensionally arranged around the vehicle to surround the vehicle corresponding to the vehicle in a non-inclined state, and the viewpoint image generating unit includes a projection plane setting unit that sets the virtual projection plane to cancel out the inclination of the vehicle, based on the inclination information; and an output image generating unit that generates and outputs output image data in order to cause a display device to display an output image (Gout, Gout1, Gout11, Gout12, Gout21, Gout31, Gout32) in which an own vehicle model image having an inclination according to an inclination of the vehicle corresponding to the inclination information is superimposed on the viewpoint image, wherein the virtual projection plane has a bottom surface (Spg) which is disposed to face a horizontal surface (Gr), and a side surface (Sps) which is disposed to face a circumference of the vehicle in a horizontal direction, and characterised in that the bottom surface has a plurality of sub-bottom surfaces (SpgRF, SpgRR, SpgLF, SpgLR) each of which is capable of being independently inclined to include a ground contact surface of each wheel of the vehicle or to be parallel to the ground contact surface. a viewpoint image generating unit that generates a viewpoint image (GIb) viewed from a predetermined virtual viewpoint (Ep) when it is assumed that a surrounding image corresponding to surrounding image data is projected on a virtual projection plane (Sp, Spi), based on inclination information corresponding to an inclination of the vehicle and the surrounding image data obtained by capturing an image of a periphery of the vehicle, wherein the virtual projection plane (Sp, Sp1) is set to be three-dimensionally arranged around the vehicle to surround the vehicle corresponding to the vehicle in a non-inclined state, and the viewpoint image generating unit includes a projection plane setting unit that sets the virtual projection plane to cancel out the inclination of the vehicle, based on the inclination information; and an output image generating unit that generates and outputs output image data in order to cause a display device to display an output image (Gout, Gout1, Gout11, Gout12, Gout21, Gout31, Gout32) in which an own vehicle model image having an inclination according to an inclination of the vehicle corresponding to the inclination information is superimposed on the viewpoint image, wherein the virtual projection plane has a bottom surface (Spg) which is disposed to face a horizontal surface (Gr), and a side surface (Sps) which is disposed to face a circumference of the vehicle in a horizontal direction, and characterised in that the bottom surface has a plurality of sub-bottom surfaces (SpgRF, SpgRR, SpgLF, SpgLR) each of which is capable of being independently inclined to include a ground contact surface of each wheel of the vehicle or to be parallel to the ground contact surface.