diff --git a/src/math/Box2.js b/src/math/Box2.js
index 4e93c616b2b0315e84a709ceba0e0ad3b60f9387..65f6ebe310030b03c1f745d7d0323172bb4f1fec 100644
--- a/src/math/Box2.js
+++ b/src/math/Box2.js
@@ -4,7 +4,7 @@
 
 THREE.Box2 = function ( min, max ) {
 
-	this.min = ( min !== undefined ) ? min : new THREE.Vector2( Infinity, Infinity );
+	this.min = ( min !== undefined ) ? min : new THREE.Vector2( + Infinity, + Infinity );
 	this.max = ( max !== undefined ) ? max : new THREE.Vector2( - Infinity, - Infinity );
 
 };
@@ -69,7 +69,7 @@ THREE.Box2.prototype = {
 
 	makeEmpty: function () {
 
-		this.min.x = this.min.y = Infinity;
+		this.min.x = this.min.y = + Infinity;
 		this.max.x = this.max.y = - Infinity;
 
 		return this;
diff --git a/src/math/Box3.js b/src/math/Box3.js
index 117aaf01c952a589f6b178464aff41a99b95b4ae..ed9208ddf0be27a4e2b6033cc23e3a7789649b0f 100644
--- a/src/math/Box3.js
+++ b/src/math/Box3.js
@@ -5,7 +5,7 @@
 
 THREE.Box3 = function ( min, max ) {
 
-	this.min = ( min !== undefined ) ? min : new THREE.Vector3( Infinity, Infinity, Infinity );
+	this.min = ( min !== undefined ) ? min : new THREE.Vector3( + Infinity, + Infinity, + Infinity );
 	this.max = ( max !== undefined ) ? max : new THREE.Vector3( - Infinity, - Infinity, - Infinity );
 
 };
@@ -147,7 +147,7 @@ THREE.Box3.prototype = {
 
 	makeEmpty: function () {
 
-		this.min.x = this.min.y = this.min.z = Infinity;
+		this.min.x = this.min.y = this.min.z = + Infinity;
 		this.max.x = this.max.y = this.max.z = - Infinity;
 
 		return this;