To form a simple and highly portable massager into a shape of an "iron club of ogre" which has recesses/projections and gives an effect similar to an acupressure force by clamping it between the back and a vehicle or a sofa, pushing it toward the backrest side by a user's weight and generating the acupressure force to the stiffness in the back, in the massager with projections for massaging the stiffness by oneself at a site when a person so desires.

This ogre's iron club-shaped, simple and portable massager using the recessed/projecting shape of the "iron club of ogre" whose story is handed down in Japan from old times, has the shape of the "iron club of ogre" and has a mini and portable size with a whole length of approximately 20 cm. This massager is clamped between the back and the backrest of a chair in particular to generate the acupressure force to the back by the dead weight, and consists of a body part 1 which has multiple projections 2 at the thick rod-shaped part, a grip part 3 which is held by the hand, a ring part 4 for facilitating to insert fingers and hold it, binding a tuft or string and having its end also useful for the massage, and the string 5 for preventing a fall and facilitating its recovery after the use.