In a system having a handsfree function to answer an incoming call handsfree and another function, when an incoming call arrives, a handsfree unit informs a user about an arrival of the incoming call and sets a user operation invalid state in which any user operation is made invalid during a predetermined period. The handsfree unit regards a user operation performed after the predetermined period passes as an operation for the incoming call, and performs incoming call answering processing corresponding to the user operation. When a user operation is performed in the user operation invalid state, the handsfree unit causes the user operation to be invalid.