A blood glucose meter comprising: a blood glucose measuring section adapted to, in a state where a measuring tip is mounted, detect blood spotted onto the measuring tip, and output a signal corresponding to the glucose level of the blood; a tip mounting processing section adapted to confirm whether or not the measuring tip has been mounted on the blood glucose measuring section; a blood spotting standby processing section adapted to confirm whether or not the blood has been spotted onto the measuring tip; a measurement processing section adapted to obtain a blood glucose value based on the signal outputted from the blood glucose measuring section; a case in which the tip mounting processing section, the blood spotting standby processing section and the measurement processing section are housed; and an internal temperature sensor disposed inside the case; characterized by an external temperature sensor disposed in a peripheral portion of the case separated from the internal temperature sensor; a temperature check processing section adapted to compare temperature difference between the internal temperature sensor and the external temperature sensor with a predetermined threshold to judge whether or not the change of the ambient temperature of the case is suitable for measuring blood glucose level; and a controller adapted to temporarily stop, if the temperature check processing section judges that it is not suitable for measuring blood glucose level when the tip mounting processing section or the blood spotting standby processing section is in operation, the processing of the tip mounting processing section or the processing of the blood spotting standby processing section until the temperature check processing section judges that it is suitable for measuring blood glucose level. a blood glucose measuring section adapted to, in a state where a measuring tip is mounted, detect blood spotted onto the measuring tip, and output a signal corresponding to the glucose level of the blood; a tip mounting processing section adapted to confirm whether or not the measuring tip has been mounted on the blood glucose measuring section; a blood spotting standby processing section adapted to confirm whether or not the blood has been spotted onto the measuring tip; a measurement processing section adapted to obtain a blood glucose value based on the signal outputted from the blood glucose measuring section; a case in which the tip mounting processing section, the blood spotting standby processing section and the measurement processing section are housed; and an internal temperature sensor disposed inside the case; an external temperature sensor disposed in a peripheral portion of the case separated from the internal temperature sensor; a temperature check processing section adapted to compare temperature difference between the internal temperature sensor and the external temperature sensor with a predetermined threshold to judge whether or not the change of the ambient temperature of the case is suitable for measuring blood glucose level; and a controller adapted to temporarily stop, if the temperature check processing section judges that it is not suitable for measuring blood glucose level when the tip mounting processing section or the blood spotting standby processing section is in operation, the processing of the tip mounting processing section or the processing of the blood spotting standby processing section until the temperature check processing section judges that it is suitable for measuring blood glucose level.