An image processing sensor comprising: an illumination unit that is configured to illuminate a target object; an imaging unit that is configured to image the target object illuminated by the illumination unit; a display unit that is configured to display an image of the target object acquired by the imaging unit; and a casing having an internal space that houses the illumination unit, the imaging unit, and the display unit, wherein the casing includes: a first casing member having a bottom portion and a first side surface (211 to 214) that extends in a direction substantially orthogonal to the bottom portion so as to surround an outer peripheral edge portion of the bottom portion, and housing the illumination unit and the imaging unit; a second casing member provided with a display window (221, 222) that allows visual check of a display screen of the display unit from outside; and a third casing member having a second side surface (231 to 234) that extends in a direction substantially orthogonal to the bottom portion of the first casing member, wherein the second side surface (231 to 234) of the third casing member is coupled to an upper surface of the first side surface (211 to 214) of the first casing member, wherein the second casing member is coupled to an upper surface of the second side surface (231 to 234)of the third casing member, the image processing sensor being characterized in that the first casing member houses a processing unit that is configured to perform pass/fail determination of the target object by processing the image of the target object acquired by the imaging unit, the third casing member includes a space partitioning portion formed substantially parallel to the bottom portion of the first casing member so as to divide the internal space into two parts; a first space portion that houses the illumination unit and the imaging unit and a second space portion that houses the display unit, and heat conductivity of each of the second side surface (231 to 234) of the third casing member and the space partitioning portion is lower than a heat conductivity of the first casing member. an illumination unit that is configured to illuminate a target object; an imaging unit that is configured to image the target object illuminated by the illumination unit; a display unit that is configured to display an image of the target object acquired by the imaging unit; and a casing having an internal space that houses the illumination unit, the imaging unit, and the display unit, wherein the casing includes: a first casing member having a bottom portion and a first side surface (211 to 214) that extends in a direction substantially orthogonal to the bottom portion so as to surround an outer peripheral edge portion of the bottom portion, and housing the illumination unit and the imaging unit; a second casing member provided with a display window (221, 222) that allows visual check of a display screen of the display unit from outside; and a third casing member having a second side surface (231 to 234) that extends in a direction substantially orthogonal to the bottom portion of the first casing member, a first casing member having a bottom portion and a first side surface (211 to 214) that extends in a direction substantially orthogonal to the bottom portion so as to surround an outer peripheral edge portion of the bottom portion, and housing the illumination unit and the imaging unit; a second casing member provided with a display window (221, 222) that allows visual check of a display screen of the display unit from outside; and a third casing member having a second side surface (231 to 234) that extends in a direction substantially orthogonal to the bottom portion of the first casing member, wherein the second side surface (231 to 234) of the third casing member is coupled to an upper surface of the first side surface (211 to 214) of the first casing member, wherein the second casing member is coupled to an upper surface of the second side surface (231 to 234)of the third casing member, the first casing member houses a processing unit that is configured to perform pass/fail determination of the target object by processing the image of the target object acquired by the imaging unit, the third casing member includes a space partitioning portion formed substantially parallel to the bottom portion of the first casing member so as to divide the internal space into two parts; a first space portion that houses the illumination unit and the imaging unit and a second space portion that houses the display unit, and heat conductivity of each of the second side surface (231 to 234) of the third casing member and the space partitioning portion is lower than a heat conductivity of the first casing member.