A blood test apparatus comprising: a housing; and an electrical circuit section built in the housing for analyzing an electrical signal from a blood sensor; the blood test apparatus having an attaching part for attaching the blood sensor, the attaching part being provided in a surface of the housing, wherein the attaching part includes a horizontal surface, formed horizontally with respect to an upper surface of the housing, and an upstanding wall surface and a vertical surface that are formed vertically with respect to the upper surface of the housing, characterised in that a surface color of a surface of the attaching part, where said surface is at least one of the horizontal surface, the upstanding wall surface and the vertical surface, has a higher color value than a color value of a surface color of the housing around the attaching part and is a color that can be identified by eyes with impaired blue cones, a hue of the surface color of said surface of the attaching part is in a range from an orange color to a red color with a wavelength of 600 to 700 nanometers, and a color value of the surface color of the attaching part defined by the Munsell color system is between 9.5 and 7, a hue of the surface color of the housing around the attaching part is in a range from a purple color, a blue color to a green color with a wavelength of 400 to 550 nanometers, and a color value of the surface color of the housing around the attaching part defined by a Munsell color system is between 1 and 4, the attaching part is shaped to project from the upper surface of the housing, the horizontal surface of the attaching part extends to a projecting part of the attaching part projecting beyond a side of the housing, and the attaching part has a shape that becomes narrower toward an interior of the blood test apparatus. a housing; and an electrical circuit section built in the housing for analyzing an electrical signal from a blood sensor; the blood test apparatus having an attaching part for attaching the blood sensor, the attaching part being provided in a surface of the housing, wherein the attaching part includes a horizontal surface, formed horizontally with respect to an upper surface of the housing, and an upstanding wall surface and a vertical surface that are formed vertically with respect to the upper surface of the housing, characterised in that a surface color of a surface of the attaching part, where said surface is at least one of the horizontal surface, the upstanding wall surface and the vertical surface, has a higher color value than a color value of a surface color of the housing around the attaching part and is a color that can be identified by eyes with impaired blue cones, a hue of the surface color of said surface of the attaching part is in a range from an orange color to a red color with a wavelength of 600 to 700 nanometers, and a color value of the surface color of the attaching part defined by the Munsell color system is between 9.5 and 7, a hue of the surface color of the housing around the attaching part is in a range from a purple color, a blue color to a green color with a wavelength of 400 to 550 nanometers, and a color value of the surface color of the housing around the attaching part defined by a Munsell color system is between 1 and 4, the attaching part is shaped to project from the upper surface of the housing, the horizontal surface of the attaching part extends to a projecting part of the attaching part projecting beyond a side of the housing, and the attaching part has a shape that becomes narrower toward an interior of the blood test apparatus.