To provide a speech signal transmission system and speech signal transmitting method with which the quality of a decoded speech signal right after frame loss can be improved.

A speech signal transmitter 101 encodes a speech signal on the premise that the speech signal has no frame loss in the past to generate 1st speech encoded information, encodes the speech signal on the premise that the speech signal has frame loss in the past to generate 2nd speech encoded information, and multiplexes and transmits the 1st and 2nd pieces of speech encoded information as speech encoded information. A speech signal receiver 102 decodes the 1st speech encoded information when detecting no frame loss of a received speech signal obtained by receiving the speech encoded information and decodes the 2nd speech encoded information in the frame right after a lost frame when detecting the frame loss of the received speech signal.