Bulb-shaped lamp and lighting device

A bulb-type lamp having both heat dissipation and size/weight reduction properties with a lower thermal load on a lighting circuit. An LED module is mounted in a case with a base member to allow dissipation of heat. An LED mount member closes another end of the case and allows conduction of heat to the case. A lighting circuit receives power via the base member. The lighting circuit is disposed inside a circuit holder. An air space exists between the circuit holder and both the case and the mount member. The lighting circuit is isolated from the air space by the circuit holder. A relationship 0.5≦S/S≦3.0, is satisfied where S denotes an area of a portion of the mount member in contact with the case and S denotes an area of the portion of the mount member in contact with a substrate of the LED module.