An electric assist bicycle comprising: a driving unit including a motor; a front wheel and a rear wheel; wherein the electric assist bicycle is capable of traveling by adding an auxiliary driving force generated by the motor to a human power driving force generated by a pedaling force from a pedal, wherein the driving unit is installed at an intermediate location between the front wheel and the rear wheel, wherein a resultant force transmitting body that is freely rotatable by a resultant force that is a combination of the human power driving force and the auxiliary driving force, a driving force output shaft body to which rotation of the resultant force transmitting body is transmitted, and a gear shift mechanism which includes a plurality of selectable gear shift stages having different gear ratios and transmits a driving force to the resultant force transmitting body, are provided in the driving unit, wherein the gear shift mechanism includes a plurality of transmission gears that includes a low speed stage transmission gear and a high speed stage transmission gear, and a gear shift stage switching body that moves in accordance with a selected gear shift stage, and wherein a switching body moving mechanism including a gear shift stage switching driving source that generates a driving force which moves the gear shift stage switching body is installed in the driving unit or in the vicinity of the driving unit, characterized in that a shaft center of a rotation shaft of the motor which generates the auxiliary driving force and a shaft center of a crank shaft on which the human power driving force acts are different from each other. a driving unit including a motor; a front wheel and a rear wheel; wherein the electric assist bicycle is capable of traveling by adding an auxiliary driving force generated by the motor to a human power driving force generated by a pedaling force from a pedal, wherein the driving unit is installed at an intermediate location between the front wheel and the rear wheel, wherein a resultant force transmitting body that is freely rotatable by a resultant force that is a combination of the human power driving force and the auxiliary driving force, a driving force output shaft body to which rotation of the resultant force transmitting body is transmitted, and a gear shift mechanism which includes a plurality of selectable gear shift stages having different gear ratios and transmits a driving force to the resultant force transmitting body, are provided in the driving unit, wherein the gear shift mechanism includes a plurality of transmission gears that includes a low speed stage transmission gear and a high speed stage transmission gear, and a gear shift stage switching body that moves in accordance with a selected gear shift stage, and wherein a switching body moving mechanism including a gear shift stage switching driving source that generates a driving force which moves the gear shift stage switching body is installed in the driving unit or in the vicinity of the driving unit, characterized in that a shaft center of a rotation shaft of the motor which generates the auxiliary driving force and a shaft center of a crank shaft on which the human power driving force acts are different from each other.