An image pickup apparatus capable of maintaining accuracy of positioning a sealing member and also applying a proper elastic repulsion force to an image pickup device. A first holding member holds an image pickup device, a first optical member is disposed forward of the device in a first direction orthogonal to an image pickup surface of the device, and a sealing member is sandwiched and held between the first optical member and the device. The first holding member has an opening portion for guiding light flux having passed through a photographing optical system to the device, and an abutment surface brought into contact with part of the first optical member. The sealing member has protrusions each extending forward in the first direction, along an outer shape of the first optical member inside the opening portion of the first holding member, as viewed in the first direction.