Earring or brooch back for receiving a post which is provided with at least one groove, comprising: a housing comprising a bottom shell and a top shell, wherein the bottom shell and the top shell are provided with mutually aligned openings (111, 121) for forming a passage for the post; a first and a second pressing element (130, 140) between the bottom shell and the top shell, wherein the first pressing element is provided with a first stop for the post and a first protruding part which protrudes from the housing, wherein the passage lies between the first stop and the first protruding part, and wherein the second pressing element is provided with a second stop for the post and with a second protruding part which protrudes from the housing, wherein the passage lies between the second stop and the second protruding part, wherein the first and second stop lie on either side of a post to be inserted; at least one spring (150; 150a, 150b) for spring-mounting the first and second pressing element; characterized in that the bottom shell is formed on the inner side with a first internal guide part for guiding the first pressing element and with a second internal guide part for guiding the second pressing element, wherein the first and second internal guide part (113, 114) lie on either side of the passage for the post. wherein the first and the second pressing element (130, 140) are provided with respectively at least a first and a second guide wall (135, 145) against which the at least one spring acts for the purpose of pressing respectively the first and second protruding part outward, which first guide wall lies substantially between the passage and the first protruding part and which second guide wall lies substantially between the passage and the second protruding part, such that the distance (d) between the first stop and the second stop can be increased by pressing the first and second protruding part inward; wherein the at least one spring has a first spring-mounted leg against the first guide wall and a second spring-mounted leg against the second guide wall. a housing comprising a bottom shell and a top shell, wherein the bottom shell and the top shell are provided with mutually aligned openings (111, 121) for forming a passage for the post; a first and a second pressing element (130, 140) between the bottom shell and the top shell, wherein the first pressing element is provided with a first stop for the post and a first protruding part which protrudes from the housing, wherein the passage lies between the first stop and the first protruding part, and wherein the second pressing element is provided with a second stop for the post and with a second protruding part which protrudes from the housing, wherein the passage lies between the second stop and the second protruding part, wherein the first and second stop lie on either side of a post to be inserted; at least one spring (150; 150a, 150b) for spring-mounting the first and second pressing element; characterized in that the bottom shell is formed on the inner side with a first internal guide part for guiding the first pressing element and with a second internal guide part for guiding the second pressing element, wherein the first and second internal guide part (113, 114) lie on either side of the passage for the post. wherein the first and the second pressing element (130, 140) are provided with respectively at least a first and a second guide wall (135, 145) against which the at least one spring acts for the purpose of pressing respectively the first and second protruding part outward, which first guide wall lies substantially between the passage and the first protruding part and which second guide wall lies substantially between the passage and the second protruding part, such that the distance (d) between the first stop and the second stop can be increased by pressing the first and second protruding part inward; wherein the at least one spring has a first spring-mounted leg against the first guide wall and a second spring-mounted leg against the second guide wall.