To provide a combustion device for a solid fuel, in which an introduction amount of combustion air can be adjusted in a stepless manner, capable of easily adjusting an opening amount of an air supply port.

A combustion device for a solid fuel includes: an air supply port 12 opened in a circular shape on a main body 2 of the combustion device to communicate with a combustion chamber; an opening/closing member 51 formed in a deformed spherical shape where at least a part of a sphere is cut off, and formed in a circular shape of a diameter larger than that of the air supply port 12 so as to allow a part of the spherical part to fit in the air supply port 12 and cover the same fully at the maximum and also cover the same partially; and holding means 52 related to the deformed spherical shaped opening/closing member 51 for holding the deformed spherical shaped opening/closing member 51 to prevent the same from falling to the outside of the main body 2 from the air supply port 12, including a case when the deformed spherical shaped opening/closing member 51 is fitted to the air supply port 12 so as not to cover a part of the air supply port 12 by the cut off part of the sphere.