A fire alarm comprising: a wireless communication terminal configured to perform wireless communication at a first frequency and a second frequency which are different from each other, a sensor configured to sense a fire; and an acoustic section configured to produce an alarm sound in accordance with sensing of the fire, the wireless communication terminal comprising: a first antenna element; a second antenna element; and a wireless circuit configured to perform at least one of transmission or reception of a radio signal via the first antenna element and the second antenna element, the wireless communication terminal being configured such that when the wireless communication terminal performs the wireless communication at the first frequency, the first antenna element is in an electric power receiving state and the second antenna element is in a grounded state, the wireless communication terminal being configured such that when the wireless communication terminal performs the wireless communication at the second frequency, the second antenna element is in an electric power receiving state and the first antenna element is in an opened or grounded state, the fire alarm being configured to, when the sensor senses the fire, transmit a cooperation signal to another fire alarm at the first frequency, the cooperation signal being a signal for causing the another fire alarm to produce the alarm sound in a cooperative manner, the fire alarm being configured to, when the sensor senses the fire, transmit a notification signal to a communication device at the second frequency, the notification signal being a signal for externally giving a notification of the fire. a wireless communication terminal configured to perform wireless communication at a first frequency and a second frequency which are different from each other, a sensor configured to sense a fire; and an acoustic section configured to produce an alarm sound in accordance with sensing of the fire, a sensor configured to sense a fire; and an acoustic section configured to produce an alarm sound in accordance with sensing of the fire, the wireless communication terminal comprising: a first antenna element; a second antenna element; and a wireless circuit configured to perform at least one of transmission or reception of a radio signal via the first antenna element and the second antenna element, the wireless communication terminal being configured such that when the wireless communication terminal performs the wireless communication at the first frequency, the first antenna element is in an electric power receiving state and the second antenna element is in a grounded state, the wireless communication terminal being configured such that when the wireless communication terminal performs the wireless communication at the second frequency, the second antenna element is in an electric power receiving state and the first antenna element is in an opened or grounded state, the fire alarm being configured to, when the sensor senses the fire, transmit a cooperation signal to another fire alarm at the first frequency, the cooperation signal being a signal for causing the another fire alarm to produce the alarm sound in a cooperative manner, the fire alarm being configured to, when the sensor senses the fire, transmit a notification signal to a communication device at the second frequency, the notification signal being a signal for externally giving a notification of the fire. a first antenna element; a second antenna element; and a wireless circuit configured to perform at least one of transmission or reception of a radio signal via the first antenna element and the second antenna element, the wireless communication terminal being configured such that when the wireless communication terminal performs the wireless communication at the first frequency, the first antenna element is in an electric power receiving state and the second antenna element is in a grounded state, the wireless communication terminal being configured such that when the wireless communication terminal performs the wireless communication at the second frequency, the second antenna element is in an electric power receiving state and the first antenna element is in an opened or grounded state, the fire alarm being configured to, when the sensor senses the fire, transmit a cooperation signal to another fire alarm at the first frequency, the cooperation signal being a signal for causing the another fire alarm to produce the alarm sound in a cooperative manner, the fire alarm being configured to, when the sensor senses the fire, transmit a notification signal to a communication device at the second frequency, the notification signal being a signal for externally giving a notification of the fire.