A system for compensating light intensity of a light source for measuring an analyte of a biological sample on the basis of reaction properties of light irradiated from the light source, the system comprising: a measurement device having a light source, a light receiving element, a controller and an inner space for receiving a cassette; and a check cassette having at least two reaction surfaces (315, 325) on the opposite surfaces that is used in the measurement device so as to compensate the light intensity of the light source, characterized in that the check cassette comprises: a first surface which has a first reaction surface having a first specific reaction property to specific light wherein the first specific reaction property of the first reaction surface to the specific light is measured on the basis of reaction properties of light irradiated from the light source of the measurement device including at least one of reflection, absorption, and transmission of the light; and a second surface which is disposed opposite the first surface and has a second reaction surface having a second specific reaction property to the specific light wherein the second specific reaction property of the second reaction surface to the specific light is measured on the basis of reaction properties of light irradiated from a light source of the measurement device including at least one of reflection, absorption, and transmission of the light, wherein information of the first reaction property of the first reaction surface is measured only when the check cassette is inserted into the inner space of the measurement device in a first state of one direction, and information of the second reaction property of the second reaction surface is measured only when the check cassette is inserted into the inner space of the measurement device in a second state of the other direction, and wherein the controller is configured to compensate the light intensity of the light source of the measurement device on the basis of the information of the first specific reaction property and the information of the second specific reaction property. a measurement device having a light source, a light receiving element, a controller and an inner space for receiving a cassette; and a check cassette having at least two reaction surfaces (315, 325) on the opposite surfaces that is used in the measurement device so as to compensate the light intensity of the light source, characterized in that the check cassette comprises: a first surface which has a first reaction surface having a first specific reaction property to specific light wherein the first specific reaction property of the first reaction surface to the specific light is measured on the basis of reaction properties of light irradiated from the light source of the measurement device including at least one of reflection, absorption, and transmission of the light; and a second surface which is disposed opposite the first surface and has a second reaction surface having a second specific reaction property to the specific light wherein the second specific reaction property of the second reaction surface to the specific light is measured on the basis of reaction properties of light irradiated from a light source of the measurement device including at least one of reflection, absorption, and transmission of the light, wherein information of the first reaction property of the first reaction surface is measured only when the check cassette is inserted into the inner space of the measurement device in a first state of one direction, and information of the second reaction property of the second reaction surface is measured only when the check cassette is inserted into the inner space of the measurement device in a second state of the other direction, and wherein the controller is configured to compensate the light intensity of the light source of the measurement device on the basis of the information of the first specific reaction property and the information of the second specific reaction property. a first surface which has a first reaction surface having a first specific reaction property to specific light wherein the first specific reaction property of the first reaction surface to the specific light is measured on the basis of reaction properties of light irradiated from the light source of the measurement device including at least one of reflection, absorption, and transmission of the light; and a second surface which is disposed opposite the first surface and has a second reaction surface having a second specific reaction property to the specific light wherein the second specific reaction property of the second reaction surface to the specific light is measured on the basis of reaction properties of light irradiated from a light source of the measurement device including at least one of reflection, absorption, and transmission of the light, wherein information of the first reaction property of the first reaction surface is measured only when the check cassette is inserted into the inner space of the measurement device in a first state of one direction, and information of the second reaction property of the second reaction surface is measured only when the check cassette is inserted into the inner space of the measurement device in a second state of the other direction, and wherein the controller is configured to compensate the light intensity of the light source of the measurement device on the basis of the information of the first specific reaction property and the information of the second specific reaction property.