There is provided an action part for a piano, which has higher rigidity than that of an action part made only of a synthetic resin, while maintaining advantageous effects as provided by the use of the synthetic resin, thereby making it possible to obtain the sound volume with a smaller key depression energy, and enhance responsiveness of the action. The action part is pivotally moved along with depression of key to thereby transmit key depression energy generated by depression of the key, to a hammer. The action part is formed by a molded article of a thermoplastic resin that is molded by a long fiber process and contains long fibers for reinforcement.