Abstract: A lock mechanism in an IC socket in which a socket substrate including an IC press cover is pivotally attached at one end thereof with a lock lever resiliently supported in such a manner as to be biased in a retaining direction. The lock lever is engaged in one end of the IC press cover by biasing the lock lever foward under a resilient supporting force. The engagement is released by pivoting the lock lever rearward against the resilient supporting force. The lock lever is provided with a hook portion extending from a pivotally supported portion of the lock lever and adapted to engage with and disengage from the end portion of the IC press cover, and a push-down operating portion projecting rearward of the hook portion from the pivotally supported portion. The push-down operating portion projects rearwardly of an end face of the socket substrate.