Lock-releasing mechanism for telephone set with muting function

In a telephone set comprising a handset having a transmitter at one end thereof and a receiver at the other end, a cradle for supporting said handset at opposite ends thereof, and a locking mechanism which stationarily retains said handset on said cradle, a lock-releasing apparatus comprising a lock-releasing button which is provided on said handset and a muting switch on said handset, said muting switch being made operative by being interlocked with the operation of said lock-releasing button, whereby any voice at a first party end can be intercepted against transmission to another party when said muting switch is actuated by said lock-releasing button.