A pneumatic radiation air conditioner including: a radiation unit configured to radiate air-conditioning air; and a fan configured to feed the air-conditioning air to the radiation unit, wherein the radiation unit includes: a first chamber, through which the air-conditioning air flows; a second chamber configured to take in the air-conditioning air discharged from the first chamber and discharge the air-conditioning air and radiate heat of the air-conditioning air to a space to be air conditioned; and an air stream adjuster configured to adjust air velocity distribution and air volume distribution of the air-conditioning air that is discharged from the first chamber to the second chamber; the air stream adjuster including a through-hole, through which the air-conditioning air is discharged to the second chamber; characterized in that the air stream adjuster further comprises: a guide disposed in the through-hole and configured to guide an air stream; and an airflow path that is a space between the guide and the through-hole, the airflow path being configured such that an area of passage of the air stream in the airflow path increases from an upwind side to a downwind side; wherein the guide includes: a support portion disposed such that a gap is formed between the support portion and a peripheral surface of the through-hole; and a flap portion provided downwind of the support portion, the flap portion being sloped in a manner to expand from the upwind side to the downwind side, the flap portion being configured to change an advancing direction of the air-conditioning air that passes through the gap between the support portion and the peripheral surface of the through-hole. a radiation unit configured to radiate air-conditioning air; and a fan configured to feed the air-conditioning air to the radiation unit, wherein the radiation unit includes: a first chamber, through which the air-conditioning air flows; a second chamber configured to take in the air-conditioning air discharged from the first chamber and discharge the air-conditioning air and radiate heat of the air-conditioning air to a space to be air conditioned; and an air stream adjuster configured to adjust air velocity distribution and air volume distribution of the air-conditioning air that is discharged from the first chamber to the second chamber; a first chamber, through which the air-conditioning air flows; a second chamber configured to take in the air-conditioning air discharged from the first chamber and discharge the air-conditioning air and radiate heat of the air-conditioning air to a space to be air conditioned; and an air stream adjuster configured to adjust air velocity distribution and air volume distribution of the air-conditioning air that is discharged from the first chamber to the second chamber; the air stream adjuster including a through-hole, through which the air-conditioning air is discharged to the second chamber; characterized in that the air stream adjuster further comprises: a guide disposed in the through-hole and configured to guide an air stream; and an airflow path that is a space between the guide and the through-hole, the airflow path being configured such that an area of passage of the air stream in the airflow path increases from an upwind side to a downwind side; a through-hole, through which the air-conditioning air is discharged to the second chamber; characterized in that the air stream adjuster further comprises: a guide disposed in the through-hole and configured to guide an air stream; and an airflow path that is a space between the guide and the through-hole, the airflow path being configured such that an area of passage of the air stream in the airflow path increases from an upwind side to a downwind side; a support portion disposed such that a gap is formed between the support portion and a peripheral surface of the through-hole; and a flap portion provided downwind of the support portion, the flap portion being sloped in a manner to expand from the upwind side to the downwind side, the flap portion being configured to change an advancing direction of the air-conditioning air that passes through the gap between the support portion and the peripheral surface of the through-hole.