Abstract: A chair for easy-sitting and easy-rising motions includes: a seat plate; a base that contacts the ground under the seat plate and supports a structure of the chair; an extensible support unit whose upper end portion is pivotably fixed to a rear portion of the seat plate and lower end portion is pivotably fixed to a front portion of the base; a second support rod whose upper end portion is pivotably fixed to the front portion of the seat plate and lower end portion is pivotably fixed to the rear portion of the base; and a guide rod that guides pivotal movements of the extensible support unit and the second support rod. When a user's weight is applied to the seat plate, since the seat plate is slowly lowered by changing its angle, the user may easily and safely sit on the chair, and the user may also easily rise from the chair.