Disclosed is a method in which a terminal provides a Mission Critical Push To Talk (MCPTT) service. The method includes receiving a group call announcement message by the terminal, which is any one of a plurality of terminals participating in a group call that is set based on the MCPTT service, comparing information regarding a first group call stored in the terminal with information regarding a second group call included in the received group call announcement message, and merging the first group call, in which the terminal is participating, and the second group call, based on a result of the comparison.