A voice recognition server 200 has a voice reception unit 202 which receives a voice from a telephone equipment 100, a model storage unit 208 which stores at least one acoustic model and at least one language model used for converting the voice received by the voice reception unit 202, to character data, a number decision unit 204 which decides a current calling number and a second number of the telephone equipment 100, a model selection unit 206 which selects an acoustic model stored in the model storage unit 208, based on the current calling number and the second number, and which selects a language model stored in the model storage unit 208, based on the current calling number, and a voice recognition unit 210 which converts the voice received by the voice reception unit 202, to character data, based on the acoustic model and the language model selected by the model selection unit 206.