An analyzer comprising: - a drive mechanism having a stepping motor as a power source; - a flow channel (501, 604) for guiding a gas-liquid fluid; - a liquid dispense pipette formed by a syringe (203, 607) and a plunger acting as pressure difference generation means for generating a pressure difference for sucking or delivering liquids and air from or to said flow channel (501, 604) to create said gas-liquid fluid, - wherein the drive mechanism is configured to transmit power from a rotation output shaft of the stepping motor to said plunger via at least one power transmission unit, and wherein the analyzer is configured to calculate the amount of idling of the plunger stemming from the stepping motor getting driven in reverse so as to perform motion control of the drive mechanism accordingly, characterized in that it further comprises: • electrodes (504, 605) installed inside the flow channel (501, 604); • measurement means configured to detect the amount of current change over a boundary surface between air and liquid of the gas-liquid fluid in the flow channel (501, 604) using said electrodes (504, 605); in that the analyzer is further configured to calculate said amount of idling of the plunger from a difference between a time t3 and a predetermined time t2, wherein the predetermined time t2 is a time period during which the plunger is moved starting from a point where a predetermined amount of air has completely moved past the electrodes (504, 605) and has been replaced with liquid, and wherein the time t3 is the time required for the air to be moved back to the electrodes (504, 605) after a reversal of the driving direction, and in that • said analyzer is configured to determine said time t3 based on the detection of the passing of said boundary surface by the measurement means. - a drive mechanism having a stepping motor as a power source; - a flow channel (501, 604) for guiding a gas-liquid fluid; - a liquid dispense pipette formed by a syringe (203, 607) and a plunger acting as pressure difference generation means for generating a pressure difference for sucking or delivering liquids and air from or to said flow channel (501, 604) to create said gas-liquid fluid, - wherein the drive mechanism is configured to transmit power from a rotation output shaft of the stepping motor to said plunger via at least one power transmission unit, and wherein the analyzer is configured to calculate the amount of idling of the plunger stemming from the stepping motor getting driven in reverse so as to perform motion control of the drive mechanism accordingly, characterized in that it further comprises: • electrodes (504, 605) installed inside the flow channel (501, 604); • measurement means configured to detect the amount of current change over a boundary surface between air and liquid of the gas-liquid fluid in the flow channel (501, 604) using said electrodes (504, 605); in that the analyzer is further configured to calculate said amount of idling of the plunger from a difference between a time t3 and a predetermined time t2, wherein the predetermined time t2 is a time period during which the plunger is moved starting from a point where a predetermined amount of air has completely moved past the electrodes (504, 605) and has been replaced with liquid, and wherein the time t3 is the time required for the air to be moved back to the electrodes (504, 605) after a reversal of the driving direction, and in that • said analyzer is configured to determine said time t3 based on the detection of the passing of said boundary surface by the measurement means. • electrodes (504, 605) installed inside the flow channel (501, 604); • measurement means configured to detect the amount of current change over a boundary surface between air and liquid of the gas-liquid fluid in the flow channel (501, 604) using said electrodes (504, 605); in that the analyzer is further configured to calculate said amount of idling of the plunger from a difference between a time t3 and a predetermined time t2, wherein the predetermined time t2 is a time period during which the plunger is moved starting from a point where a predetermined amount of air has completely moved past the electrodes (504, 605) and has been replaced with liquid, and wherein the time t3 is the time required for the air to be moved back to the electrodes (504, 605) after a reversal of the driving direction, and in that • said analyzer is configured to determine said time t3 based on the detection of the passing of said boundary surface by the measurement means.