Provided are a protecting device and a battery pack capable of preventing floating of a blowout member, preventing deformation of a meltable conductor, and maintaining predetermined current capacity and blowout properties. The protecting device 1 includes: a meltable conductor 2; and a blowout member 4 connected to one surface of the meltable conductor 2, wherein the blowout member 4 includes: an insulating substrate 3; and a deformation suppressing electrode 5 formed on a front surface 3a connected to the meltable conductor 2 of the insulating substrate 3 and connected to the meltable conductor 2 to suppress deformation of the meltable conductor 2.