Abstract: A massage apparatus comprises an outer casing set, a chain set, and a prime mover set. The outer casing set is composed of two casings facing to each other with a curve casing wall with a longitudinal curvilinear casing groove respectively. A limit switch is disposed at both ends of the outer casing set. The chain set further comprises two wheel seats, two endless chains, two arm plates, and two pairs of sprockets, and two direction wheels. The wheel seats are disposed at two lateral sides of the outer casing set respectively and at an upper level relative to the outer casing set. Each endless chain fixedly joins with the respective wheel seat. Each arm plate pivotally connects with each wheel seat via a spindle. The respective arm plate provides a stop piece to limit a pivot angle thereof. Each direction wheel is sandwiched between the upper part and the lower part of the casing wall. The sprockets mesh with the endless chains.