Provided are a living body pressing device which can perform effective pressing at both ends in the short-side direction of the device and is reduced in size, a method of manufacturing the living body pressing device, and a blood pressure measuring device. An air bag (2) of a living body pressing device (1) compresses: an air bag body (21) having a single sheet (22) in which both ends thereof parallel to the long-side direction are folded, a fused section (23) where the folded both ends are fused together and which is located at the upper surface of the sheet, and fused sections (24) in the long-side direction where the both ends in the long-side direction are fused respectively and a reinforcing sheet (3) having a shape corresponding to the upper surface of the air bag body (21) and mounted to the upper surface of the air bag body (21) so as to cover the upper surface.
