An illuminating device includes a connecting portion supplied with power, a conversion circuit that converts power supplied from the connecting portion, a case having a tubular shape, a support body that divides the case in the radial direction, and a plurality of light emitting diodes provided on one surface of the support body. The illuminating device further includes a drive circuit that drives the light emitting diodes, a secondary battery provided on the other surface of the support body, a charge/discharge control circuit for the secondary battery, and a control section that lights the light emitting diodes by supplied power and charges the secondary battery. The control section permits lighting of the light emitting diodes by a discharge of the secondary battery in a state in which power supply is stopped.