// 例
var gjo = L.geoJson(office, {
    pointToLayer: function(feature, latlng) {
	var marker, popup;
	switch (feature.properties.dep) {
	case "fire":
	    return L.circleMarker(latlng, {
		color: "red"}).bindPopup("消防署");
	    break;
	case "police":
	    return L.circleMarker(latlng, {
		color: "black"}).bindPopup("警察署");
	    break;
	}
    }
}).addTo(mymap);
mymap.fitBounds(gjo.getBounds());