To provide a strainer, and a valve gear which can be manufactured while securing filtering performance without deteriorating productivity.

The strainer 41 (a strainer body 42) is provided with a filter part provided with a plurality of piercing pores, and ribs 45 formed on both end sides in a lateral direction of the strainer body 42. The strainer 41 is formed such that a length size L1 in the lateral direction is somewhat longer than a length size L in an axial direction of each port groove 35 and 36 formed on a circumferential wall 21A of a valve body 21. The strainer body 42 is formed such that a length size L2 in the lateral direction is shorter than the length size L in the axial direction of each port groove 35 and 36. By this, when the strainer 41 is attached in a state fit in each port groove 35 and 36, each rib 45 of the strainer 41 presses against axially opposing inner side faces 35c and 36c of each port groove 35 and 36.