A biological sample measurement device comprising: a main body case including a sensor mounting component; a measurement component connected to the sensor mounting component; a controller connected to the measurement component; a detector configured to detect a mounting of a sensor to the sensor mounting component connected to the controller; and a memory component connected to the controller, wherein an input side of the measurement component is connected to a switching component configured to switch between an open state, connection to the sensor mounting component, and connection to a first reference resistor, the controller has a measurement preparation mode and a measurement mode, the controller being operable to perform Check 01 and Check 02 in the measurement preparation mode and determine whether there is an abnormality in the measurement component, the controller being configured to connect the input side of the measurement component to the sensor mounting component for the measurement mode when the controller determines that there is no abnormality in the measurement preparation mode, wherein Check 01 and Check 02 are defined as follows: Check 01: In a state where the input side of the measurement component is connected by the switching component to the first reference resistor, the controller finds a first measurement value and determines whether or not the first measurement value is within a first reference range stored in the memory component; Check 02: In a state where the switching component puts the input side of the measurement component in an open state, the controller finds a second measurement value and determines whether or not the second measurement value is within a second reference range stored in the memory component. a main body case including a sensor mounting component; a measurement component connected to the sensor mounting component; a controller connected to the measurement component; a detector configured to detect a mounting of a sensor to the sensor mounting component connected to the controller; and a memory component connected to the controller, wherein an input side of the measurement component is connected to a switching component configured to switch between an open state, connection to the sensor mounting component, and connection to a first reference resistor, the controller has a measurement preparation mode and a measurement mode, the controller being operable to perform Check 01 and Check 02 in the measurement preparation mode and determine whether there is an abnormality in the measurement component, the controller being configured to connect the input side of the measurement component to the sensor mounting component for the measurement mode when the controller determines that there is no abnormality in the measurement preparation mode, wherein Check 01 and Check 02 are defined as follows: Check 01: In a state where the input side of the measurement component is connected by the switching component to the first reference resistor, the controller finds a first measurement value and determines whether or not the first measurement value is within a first reference range stored in the memory component; Check 02: In a state where the switching component puts the input side of the measurement component in an open state, the controller finds a second measurement value and determines whether or not the second measurement value is within a second reference range stored in the memory component. Check 01: In a state where the input side of the measurement component is connected by the switching component to the first reference resistor, the controller finds a first measurement value and determines whether or not the first measurement value is within a first reference range stored in the memory component; Check 02: In a state where the switching component puts the input side of the measurement component in an open state, the controller finds a second measurement value and determines whether or not the second measurement value is within a second reference range stored in the memory component.