A method of estimating bio-information which is performed by an electronic device (600; 700) comprising a sensor part disposed on a side of a main body with a display, and a processor, the method comprising: receiving a request for estimating bio-information; controlling the display to display a first graphical object representing an appearance of the main body including a sensor part and a second graphical object representing an appearance of a finger to guide the finger to be in normal contact with the sensor part; acquiring, by the sensor part, a contact state of a finger before measurement of a bio-signal, wherein the sensor part comprises an optical sensor and a force sensor configured to measure the contact force based on the finger contacting the finger contact surface; determining whether the contact state of the finger is normal based on at least one of an analysis whether an initial contact force is within a preset threshold range, and an analysis whether a contact force is measured for a threshold period of time; in response to the contact state being normal, controlling a display, by the processor, to display the first graphical object, the second graphical object, and a third graphical object to induce the user to apply a pressure to the sensor part with the finger for measuring the bio-signal; acquiring, by the sensor part, a contact force of the finger during the measurement of the bio-signal; controlling the display, by the processor, to display a seventh graphical object (1111, 1112) related to a reference contact force at which the finger presses the sensor part and an eighth graphical object (1121, 1122) representing an actual contact force measured through the force sensor to induce the user to press the sensor part with a predefined normal force; acquiring the bio-signal by the sensor part; and estimating bio-information based on the bio-signal and the contact force. receiving a request for estimating bio-information; controlling the display to display a first graphical object representing an appearance of the main body including a sensor part and a second graphical object representing an appearance of a finger to guide the finger to be in normal contact with the sensor part; acquiring, by the sensor part, a contact state of a finger before measurement of a bio-signal, wherein the sensor part comprises an optical sensor and a force sensor configured to measure the contact force based on the finger contacting the finger contact surface; determining whether the contact state of the finger is normal based on at least one of an analysis whether an initial contact force is within a preset threshold range, and an analysis whether a contact force is measured for a threshold period of time; in response to the contact state being normal, controlling a display, by the processor, to display the first graphical object, the second graphical object, and a third graphical object to induce the user to apply a pressure to the sensor part with the finger for measuring the bio-signal; acquiring, by the sensor part, a contact force of the finger during the measurement of the bio-signal; controlling the display, by the processor, to display a seventh graphical object (1111, 1112) related to a reference contact force at which the finger presses the sensor part and an eighth graphical object (1121, 1122) representing an actual contact force measured through the force sensor to induce the user to press the sensor part with a predefined normal force; acquiring the bio-signal by the sensor part; and estimating bio-information based on the bio-signal and the contact force.