A microchip analysis device in which the effect of changes in the quantity of light of a discharge lamp of the short arc type can be reduced and measurement results with high reliability can be obtained is achieved in microchip measurement device which has a light source lamp and a lamp operating device, in which the light from the lamp is transmitted by a fill part for the liquid of the microchip to be tested, and in which the quantity of this transmitted light and based on the data obtained the decadic extinction of the liquid to be tested are measured, a device determines the fluctuation of the quantity of light from the light source lamp. Based on data from this device, a control interrupts or stops the detection of the quantity of the light transmitted by the microchip when the fluctuation is outside a preset range.