To improve efficiency of assembling work, and to secure smoothness of the oscillation operation of a rocker arm.

This rocker arm unit is provided with a lash adjuster 40 having a plunger 41 extended axially and a cylindrical body 42 for slidably storing the plunger 41 and with the rocker arm 10 supported by an upper end part of the plunger 41 and oscillated approximately around the support position. The rocker arm unit is further provided with a clip 60 fixed to the body 42, extended to the fixed position and engaged with the rocker arm 10 to regulate dropping of the rocker arm 10 from the lash adjuster 40. The clip 60 comprises a retainer part 61 for regulating coming-off of the plunger 41 and an extension part 62 integrally extended from the retainer part 61.