The present invention relates to a message transmitting apparatus and method in a mobile communication terminal and solves the problem of a message transmission being stopped when a message size exceeds a message capacity is solved. Also, memory resources of the mobile communication terminal are more efficiently utilized because an additional memory region need not be allocated to a message to be transmitted. The apparatus comprises a message generating unit for generating a message, a buffer for temporarily storing the generated message, a controller for dividing the message stored in the buffer into data blocks, wherein the controller converts a format of the data blocks into a type capable of being transmitted or received via a network and stores the data blocks into a file, and a transmitter for transmitting the message comprising the data blocks having the converted type and stored in the file to a receiving side.