An imaging apparatus comprising: a housing member having an opening; an electronic circuit unit housed in the housing member and including an imaging device to acquire an object image formed by an imaging optical system; and at least one circuit board (32, 33, 34) having mounted thereon one or more electronic components, wherein the electronic circuit unit includes a first heat transfer member having thermal conductivity, which is in contact with an outer peripheral surface of the electronic circuit unit, wherein the first heat transfer member includes a metal plate portion and a soft material portion, wherein the first heat transfer member is adhered to the outer peripheral surface of the electronic circuit unit, wherein the soft material portion adheres to the metal plate portion, wherein the metal plate portion is in tight contact with the inner peripheral wall surface of the housing member, wherein the electronic circuit unit on which the metal plate portion is attached is configured to be insertable on the inner peripheral wall surface of the housing member along an imaging optical axis of the imaging optical system; wherein the soft material portion is made of a shape-conformable member; and wherein the heat transfer member is formed as a first heat transfer member, and further comprising a thermally-conductive second heat transfer member which extends along the circuit board (32, 33, 34) and thermally connects the electronic components and the first heat transfer member, characterized in that the electronic circuit unit includes an electromagnetic shielding plate that forms the outer peripheral surface, and the soft material portion of the first heat transfer member is in contact with the electromagnetic shielding plate. a housing member having an opening; an electronic circuit unit housed in the housing member and including an imaging device to acquire an object image formed by an imaging optical system; and at least one circuit board (32, 33, 34) having mounted thereon one or more electronic components, wherein the electronic circuit unit includes a first heat transfer member having thermal conductivity, which is in contact with an outer peripheral surface of the electronic circuit unit, wherein the first heat transfer member includes a metal plate portion and a soft material portion, wherein the first heat transfer member is adhered to the outer peripheral surface of the electronic circuit unit, wherein the soft material portion adheres to the metal plate portion, wherein the metal plate portion is in tight contact with the inner peripheral wall surface of the housing member, wherein the electronic circuit unit on which the metal plate portion is attached is configured to be insertable on the inner peripheral wall surface of the housing member along an imaging optical axis of the imaging optical system; wherein the soft material portion is made of a shape-conformable member; and wherein the heat transfer member is formed as a first heat transfer member, and further comprising a thermally-conductive second heat transfer member which extends along the circuit board (32, 33, 34) and thermally connects the electronic components and the first heat transfer member, characterized in that the electronic circuit unit includes an electromagnetic shielding plate that forms the outer peripheral surface, and the soft material portion of the first heat transfer member is in contact with the electromagnetic shielding plate.