The present invention relates to a chair with an armrest. In an embodiment, the chair with an armrest includes a support base (5) supported by a leg, a seat (6) that is pivotally fixed to the support base (5) using an axle (9) extending in a left and right direction, the rear part of the seat being rotatable upward and downward, an impelling unit (10) that is provided at the support base (5) and impels the seat (6) at the rear of the axle (9) upward, and an armrest (14) provided to the support base (5). When the rear part of the seat (6) rotates upward or downward, the height of the armrest (14) does not change, and therefore arms or the like are not squeezed between the top plate of a desk and the armrest (14).
