An image formation apparatus includes: an image former that forms an image on a recording medium delivered along a predetermined delivery path; a first hardware processor that judges whether or not the recording medium is an envelope; a second hardware processor that acquires a basis weight of the envelope; a third hardware processor that determines, in case the first hardware processor judges that the recording medium is the envelope, control for forming an image on the envelope by the image former on the basis of the basis weight of the envelope acquired by the second hardware processor.