A method for turning pages of an electronic-book, e-book, in a portable terminal having an e-book function, the method comprising: executing the e-book function; determining whether a touch down is input in a pre-set right User Interface, UI, active area of the e-book; displaying a right lateral side of the e-book and driving a 3-axis sensor to detect an inclination value of the portable terminal when the touch down is input in the pre-set right UI active area of the e-book; determining whether the inclination value greater than or equal to a threshold is detected in a left direction; upon detection of the inclination value greater than or equal to the threshold in the left direction (1111-YES), displaying a next page to a screen on a single-page basis at a speed in proportion to the inclination value detected in the process of detecting the inclination value greater than or equal to the threshold in the left direction; determining whether a drag is input to the right while maintaining the touch down input; stopping the driving of the 3-axis sensor and displaying a page number increased by an extent of the drag to the right lateral side of the e-book when the drag is input to the right while maintaining the touch down input; determining whether a touch up is input releasing the drag input to the right; driving the 3-axis sensor to detect the inclination value of the portable terminal when the touch up is input releasing the drag input to the right; determining whether the inclination value greater than or equal to the threshold is detected in the left direction; and upon detection of the inclination value greater than or equal to the threshold in the left direction (1124-YES), displaying a next page corresponding to the page number increased by the extent of the drag to the screen. executing the e-book function; determining whether a touch down is input in a pre-set right User Interface, UI, active area of the e-book; displaying a right lateral side of the e-book and driving a 3-axis sensor to detect an inclination value of the portable terminal when the touch down is input in the pre-set right UI active area of the e-book; determining whether the inclination value greater than or equal to a threshold is detected in a left direction; upon detection of the inclination value greater than or equal to the threshold in the left direction (1111-YES), displaying a next page to a screen on a single-page basis at a speed in proportion to the inclination value detected in the process of detecting the inclination value greater than or equal to the threshold in the left direction; determining whether a drag is input to the right while maintaining the touch down input; stopping the driving of the 3-axis sensor and displaying a page number increased by an extent of the drag to the right lateral side of the e-book when the drag is input to the right while maintaining the touch down input; determining whether a touch up is input releasing the drag input to the right; driving the 3-axis sensor to detect the inclination value of the portable terminal when the touch up is input releasing the drag input to the right; determining whether the inclination value greater than or equal to the threshold is detected in the left direction; and upon detection of the inclination value greater than or equal to the threshold in the left direction (1124-YES), displaying a next page corresponding to the page number increased by the extent of the drag to the screen.