A blood glucose level measuring chip exhibits excellent blood spreading ability and can maintain a reaction rate of blood with a reagent, even where the blood has a high hematocrit value (Ht). The blood glucose level measuring chip includes a blood glucose level measuring reagent including a supply port through which blood is supplied, a flow path having the supply port formed at one end of the flow path, and a blood glucose level measuring reagent containing an aromatic hydrocarbon having at least one sulfonic acid group disposed on an inner wall defining the flow path, wherein a ratio A/B is 3.7 mmol/L or more to 184.8 mmol/L when A (mmol) represents the total molar amount of aromatic hydrocarbons contained in the blood glucose level measuring reagent, and B (L) represents a volume of a region in which the blood glucose level measuring reagent and the blood are dissolved.