Abstract: A safety nap cushion for use with a chair back mainly consisting of a reverse U-shaped inflatable back cushion having a central opening, two properly curved inflatable side cushions thermally-sealed to two front sides of the back cushion to softly and fitly confine a user's head therebetween, and a length-adjustable retaining strap detachably attached to the back cushion and suitable for being pivotally turned to a position in front of the side cushions to fitly confine the latter and prevent the latter from swaying laterally under pressure. The back cushion is fixly attached to a chair back by engaging hook members with retaining rings provided at its two sides. The side cushions each has a properly curved inner side surface and are so designed that a smooth curve is formed at a lower joint between thed back cushion and the two side cushions to comfortably support the user's head.